'We were picking our baby's name when I found out who my partner really was.'

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This is Part 1 of Sarah's story. You can read Part 2 here.

Sarah thought she'd found her fairy tale when she met Phil on a dating app during a hungover Sunday morning in London.

She was 35, living her best expat life, and had just re-downloaded the app "for the hundredth time" when this handsome, charming Irishman appeared on her screen.

"He was 39, dark hair, beard, very much my type, really good photos, six-foot-three," Sarah said on Mamamia's Everyone Has An Ex podcast, narrated by Georgia Love.

Phil was everything she thought she wanted. Tall, funny, and absolutely magnetic. Despite having two children (which was normally a deal-breaker for Sarah), she found herself swept up in what felt like the romance of a lifetime.

Watch: 'But Are You Happy?' hosts Ashani and Anastasia discuss toxic relationships. Post continues after video.

When they met at her favourite pub in Notting Hill, the chemistry was undeniable.

"We got really, really, really drunk, and it was probably one of the best first dates of my life. We come from completely different countries, backgrounds, we worked in different industries, but we got along so well and had so much to talk about, which I think is quite rare."

What followed was a whirlwind European summer that felt like something out of a movie. Phil changed his flights to stay an extra night after their first date, then whisked her away to Paris for a week to see a gig.

"We saw The Killers, one of my favourite bands… we just liked all the same things, and it was fun and easy."

Phil was always available, always charming, and seemed completely devoted to her. Within two months, he told Sarah he loved her during a romantic trip to France.

"I remember I cried, and I said 'I love you too'. I don't think I've ever told a guy that I love him before in my life… actually I haven't, so there you go. That was the first time, at 35 years of age," Sarah admitted.

Phil seemed to tick every box. He wanted another child, specifically a daughter, to go with his two sons. And he promised they could move to Australia together once his boys were old enough to travel back and forth.

The 39-year-old even moved to London to be with Sarah, giving up his previous life for their relationship, while still being a devoted family man.

"I just thought he was just such a fantastic father because, no matter what was happening in London, he always went back. He never shirked his responsibilities, and he was always so respectful of his ex-wife," Sarah explained.

By four months in, Phil was asking about engagement rings. Sarah was so excited she secretly started a Pinterest board for ring inspiration, only to discover in horror that it was automatically posting to her Facebook feed. But Phil just laughed it off, and they began fertility testing together, eager to start their family.

They found a beautiful apartment and began building what felt like an ideal life together. Everything seemed perfect.

But beneath the surface, cracks were already beginning to show.

Phil's finances seemed inconsistent. He'd be generous one moment, then stressed about money the next.

Sarah found herself quietly covering more and more expenses to keep the peace.

Then came the jealousy. It started small, with Phil catching Sarah glancing at another man in a bar and getting angry.

"The mood just changed. He was furious. He was bristling. It was really awkward, and I just instantly felt sick and uncomfortable," Sarah recalled.

Soon, Phil was monitoring her every move when they were apart. "Every week when he was back (home), he would just be constantly online... he would see on one of their Instagram stories that there were guys at our table at a bar. All my girlfriends were single, and he would just start blowing up my phone, 'Who is that guy?'."

The fights became a monthly occurrence, always ending with Phil's tears and apologies. "I'm sorry, I just don't trust you," became his constant refrain.

Eventually, when a close friend pulled Sarah aside during a trip to Italy and told her "he's not the guy for you," she tried to break up with Phil. But his desperate pleas won her back.

"He broke down in tears and he begged me, 'I'll do whatever it takes. You can't leave me. I love you, I want to be with you. I want a life with you. I don't like myself like this. I've never been like this with anyone before. I've never been in love before, and I don't know how to handle it'."

So, Sarah stayed. And three weeks later, she discovered she was pregnant. Phil was overjoyed, as was Sarah, especially when they learned they were having a girl, and suggested the name Imogen.

"I cried. He cried. It's what he wanted. So we were just thrilled."

But the joy wouldn't last. Phil's jealousy intensified, the financial stress mounted, and Sarah found herself walking on eggshells, terrified of triggering another explosive fight.

Nothing could have prepared Sarah for what she was about to discover: a betrayal so shocking it would shatter everything she thought she knew about the man she loved.

To be continued…

This is Part 1 of Sarah's story. You can read Part 2 here.

Feature Image: Getty (Stock image is for illustrative purposes only).