My glamorous older sister slept with my boyfriends — and then my husband. So why have I never confronted her?

The first time my sister stole my boyfriend I was 18. Not long out of boarding school, I was living in my dad’s London flat and doing a secretarial course.

James worked in the city. The brother of a friend, he was tall, good-looking, funny and outgoing. I always felt that bit more special when he included me in the conversation. We became inseparable. James was the first man I slept with, the first man I’d ever loved, and at the time I honestly thought he was the one. We’d been seeing each other for six months when he met my older sister Libby, who, at 22, was doing a bit of modelling and had her own place.

When she drifted in one evening — all piercing blue eyes, glowing olive skin, long hair swishing around her shoulders and wearing a floaty wrap dress that showcased her décolletage — James’s jaw almost hit the floor.

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It wasn’t the first time I’d seen her inspire this reaction in men. Yet as he carried on being his usual funny, ebullient self, I reassured myself that he was just being friendly.

That was my mistake — one Libby picked up on instantly.

Shortly after she left to go home, James said he needed to get back to his place, despite the plan being that he would stay over at mine.

Though disappointed, I didn’t see any cause for alarm. From then on James started to distance himself, claiming he couldn’t meet up because of work commitments.

A couple of months later, he just stopped calling, leaving my own calls unanswered. I was confused and heartbroken, mourning what I was sure was the great love of my life.

I didn’t see Libby again after that night until Christmas when she asked if I’d seen James recently — an unusual question given she’d only met him once, and we’d not discussed him since. When I told her we’d broken up, she blushed.

But it wasn’t until a couple of months later that I pieced it together.

A friend mentioned that she’d seen them together at a bar, whispering to one another and holding hands. She nervously asked whether my sister and I ‘shared’ men.

Horrified, I laughed it off and said we’d already split. Even though inside I felt devastated, humiliated and betrayed.

You might wonder why I didn’t confront my sister, but I was only 18, and she had always been more glamorous, more imposing, and more intimidating. In our family, Libby was the sun around which my father and I revolved. I’ve always been quiet, a bit of a bookworm. And physically I was never, ever her match.

Of course, James preferred her to me.

I never had the confidence that comes with Libby’s physical perfection, and I certainly didn’t possess the maturity or self-assuredness to call her out, so I just buried the hurt I felt.

Some 18 years later, I’m definitely not laughing it off.

Because, including James, Libby has now slept with both of the boyfriends I introduced her to – and my (now ex) husband.

And yet, perversely, the complex dynamic that exists between us – one rooted in our shared childhood trauma after our mother left home without a backward glance — means I still feel powerless today, aged 36, to let rip the full extent of my pain and fury at her as I did when I was that shy, insecure teenager.

The next time it happened, I was in my late 20s. By then Libby was living in Ibiza, and the James incident was long forgiven, if not forgotten.

So when a flying visit home coincided with the weekend I was hosting a dinner party to introduce my boyfriend Will to my closest friends, I invited Libby, too.

Will was in his early 30s and worked in insurance, tall, with curly hair and gorgeous brown eyes. We’d been together for six months, and it was getting serious between us.

By then in her early 30s too, Libby was still exceptionally beautiful, with the kind of presence that lights up a room — and causes everyone else to fade into the background. Yet, at first, she blended in perfectly. It was when, around midnight, as my friends began to drift away, that things took a turn.

After they’d gone, I went into the kitchen to make coffee, which I hoped would signal to Libby that it was time for her to leave, too. Will was due to head back to his place as well, but only after (so I assumed) we’d ended the evening in bed together.

But at the sound of falling glassware, I stopped grinding the coffee and went to the dining room door, only to see Libby sat astride Will, running her fingers through his hair.

Part of me wanted to scream. How could she do this to me again? How could he? Was Libby still really so much more irresistible than me that no man could prefer me when presented with the alternative?

I think that fear, that shame, is part of the reason why – instead of making a scene – I froze.

Realising they hadn’t seen me, I silently retreated to the kitchen, shouting out to ask who wanted sugar, despite knowing perfectly well neither of them take it.

When I re-entered the room they were both back in their seats. Ten minutes later Libby’s taxi was outside and, as she gathered up her things, she casually offered Will a lift home, which he accepted, even though it wasn’t on his way.

As the door closed behind them I burst into tears. I knew what was going to happen. Libby was once again going to have sex with a man I was in love with.

That night, when Will trotted out after my sister, was the last time I heard from him. I wasn’t going to demean myself by calling him.

As for Libby? Yet again, I didn’t confront her. But I also didn’t see her again for two years.

Did she know the reason I kept her at arm’s length? Was her guilt why she didn’t reach out to me either? Perhaps if we lived nearby, if we enjoyed a close relationship, I might finally have had it out with her. But as she returned to Ibiza, I felt the best thing to do was to keep distance between us in every sense.

It was two years later when I married David, who I met through our work in the art world. He was involved in curating exhibitions and we clicked immediately.

While James and Will had been loud, extroverted characters like Libby, David was like me; both introverted, both younger children and happiest staying in and listening to music or watching television.

And he was less handsome than either of them. Now I wonder if, subconsciously, I had chosen for my husband a man I thought my sister wouldn’t be attracted to. I did send Libby an invite to the wedding, but she cried off due to being on the other side of the world for some sort of charity modelling engagement. I didn’t try to persuade her.

A year later, I decided it was time to end this impasse. So I invited myself and David to her villa in Ibiza to celebrate my 30th birthday. He was my husband. Surely, that was a line she would not cross. Now, I kick myself for being such a fool.

During our stay, she wafted around in transparent kaftans, sunbathed topless and openly flirted with him, telling him about this cove or that beach we absolutely must go to where skinny dipping was the norm.

He was utterly mesmerised.

David and I rowed nightly in our bedroom, me tearing him off a strip for looking at her breasts, him saying I was overreacting, that of course I had nothing to worry about.

There’s no way Libby could have missed our fights. If I’m honest, I cowardly hoped that her overhearing my distress would serve as a way of me addressing the issue without having to confront her.

Between the anger, pain, jealousy and fear I felt, I saw the very worst of myself on that holiday and vowed never to step foot in my sister’s home again. As David and I flew home in miserable silence, I consoled myself that at least the worst had been avoided. I was wrong.

Unable to hold in the guilt, within a month of returning home David told me that they had slept together. I honestly have no idea when they managed it; I didn’t want him to tell me.

Our divorce, after 18 months of marriage, came soon afterwards. I didn’t tell anyone the reason for our split, fearing that they’d judge me. I certainly didn’t let Libby know we had split, though I assume David did. Either way, she never contacted me.

There are two questions here.

Why do I keep falling for men who are so disloyal they will sleep with my sister? Deep down, though I know I shouldn’t, I have always blamed myself, believing that it can only be because I’m inadequate — in looks, in personality, in bed — by comparison.

But the bigger question is why have I still never confronted my sister about her behaviour.

After four years of almost radio silence, we are currently enjoying an uneasy reunion following the death of our father, as we sort through his estate. She’s now the only family I have left. Which I think is at the root of our very problematic relationship.

When I was ten, and Libby was 14, our mother moved to the Far East with a man she met at work, leaving her bewildered daughters behind to be cared for by a cash-rich, time-poor father. Neither of us has had a relationship with her since then.

Dad shunted us off to different boarding schools, and from then on we only saw each other at Dad’s in the holidays when we’d exchange stories of boarding school life, which I hated, as I wasn’t academic.

At times it was like getting to know a stranger again.

Yet I idolised her, fascinated by her tales of the boys she was seeing, of losing her virginity, of being the most popular, the most desirable girl in school – all a world away from my own experiences. I believe this is why I have never been able to stand up to her.

One of my therapists (I’m now 36 and have had several over the years to help me with self-confidence and anxiety issues) says the reason my sister sleeps with my boyfriends is that we simply never had those formative bonding years together when we would have looked out for one another. To Libby, I am just a competition.

Another therapist pointed out that male attention is how my clearly insecure sister validates herself. This tallies with the rare handful of heart-to-hearts we have had over the years.

When I was 25, Libby told me she never got over Mum leaving — or, as she puts it, abandoning — us, and it means she doesn’t trust other women.

Despite recognising the irony, I share her feelings of betrayal and the loss of mum. It’s why, despite the pain she’s caused, the thought of a confrontation with Libby that would likely sever our relationship for good too is just too much. She’s a nightmare, but she’s my nightmare, the only one I have left now Dad is gone (and in all honesty, he wasn’t really present when he was alive).

I still love her. And a very small part of me feels sympathy for her.

At this point in my life, I have found some kind of happiness. I love my work, my friends, and — since I’ve never felt the urge to become a mum — I don’t feel under time pressure to find another partner in order to have children. That, at least, is not something Libby was ever able to steal from me.

Meanwhile, as far as I’m aware, apart from a bit of modelling, Libby has never had a proper job — instead living off our father’s wealth — has few real friends and has never had a serious relationship either. My therapists have told me she won’t ever change. And I accept now that I’ll never be able to trust her.

So, sad as it may seem, I’m just left holding out hope that, one day, I’ll find a man who is happy with me, and only me.

Names have been changed. As told to Samantha Brick