I spent 3 years trying to gain my boyfriend's trust after I cheated on him. What I really needed to do was forgive myself.

• Nicola Prentis cheated on her boyfriend during his 15 months' military service.
• She spent three years trying to earn back his trust and forgiveness but it didn't work.
• Then a new guy she was dating said something very simple and she forgave herself.

One line of Dave Grohl's infidelity statement took me back to the aftermath of when I cheated on my Turkish boyfriend in Istanbul in 2008. Grohl said, "I am doing everything I can to regain their trust and earn their forgiveness." I spent three years trying to do that and it cost me entire sense of self until I finally forgave myself.

When my Turkish boyfriend was leaving for 15 months' compulsory military service, he admitted he didn't know if we were right together. I didn't either and, in his absence, the doubts and distance took their toll.

Ten months in, I cheated with a former colleague, not sure which of them to be with. By the end of the military service, I'd ended the fling, and my boyfriend returned to Istanbul. Our feelings grew stronger, and we were planning the future together.

But then he came across some incriminating messages and it all came crashing down around my ears.

I started doing everything to earn trust and forgiveness

For the next three years, I did everything to win him back: cooking and cleaning, repainting his kitchen, shunning a social life, begging, crying, staying home while he played the field with other women. Some days, as I went about my chores I'd stagger, physically winded by the knowledge of the pain I'd caused him. For his part, he tried to get past it but he would never forget and I wasn't allowed to.

The relationship became torturous. I had to prove my trustworthiness by always answering my phone or messages immediately. I had to throw out any clothes I might have worn during that period. My skin broke out worse than it ever had in my teens and I barely ate. The dramatic weight loss at least offered another way to maybe earn forgiveness because he had always liked thin girls.

Sometimes I'd have nightmares where I was shot and, as I fell to the ground, I'd cry because I was dying unabsolved. In other dreams, I'd be kissing a guy and then suddenly realize I actually had a boyfriend. I'd wake up panicking that I'd cheated again without meaning to. For the rest of the day I felt like I was hiding more cheating and that the dream proved what I really was.

Over the following months, he would throw me out or I'd leave and go back, leave again and go back again. I lurched from one job to another, often quitting after a few weeks because I was too emotionally wrung out to function. I told elaborate lies to employers about why I was quitting. I moved a lot, always to places I knew no one, both as punishment and to hide away.

The one constant person in my life was my ex with whom I was still in regular contact even when he got a new girlfriend. I avoided old friends because I couldn't face anyone seeing how lost I was or who had known the old me. The cheating had defined me for so long I didn't know who I was.

I achieved self-forgiveness through a casual comment

Then, a couple of weeks after another move, this time to Madrid, I met a guy I really liked. But, first, I had to confess so he could judge and decide whether to continue with me. To my surprise, he wasn't fazed at all.

"Cheating isn't the worst thing you can do," he said, dismissing in seconds what had haunted me for three years.

I disagreed, determined to stay penitent. "It's the worst thing you can do in a relationship," I argued.

"OK, yes." He shrugged. "But no one died."

And, in that moment, I forgave myself.

It wasn't about whether or not cheating was the biggest wrong you could do. It was that someone only saw me, not what I'd done, in turn allowing me to finally do the same.

That particular relationship didn't last but the gift of self-forgiveness that he gave me endures. I stopped contact with my ex and the years that followed were some of my happiest, personally and professionally.

I am no longer defined by the fact I cheated

I no longer cringe when I hear a story in the media about cheating or connect it to me. And I don't necessarily see prior cheating as a red flag in someone else. My experience taught me that you don't have to stay defined as "a liar" or "a cheat" as long as you've truly reflected on it and learned something.

Ten years later, in 2023, out of the blue, my ex messaged to say "I want you to know I finally made it. One day suddenly. I forgive you, Nicol [sic]. Done." I had long since stopped needing his forgiveness but I'm happy he has found the same peace as I did.