I immediately knew it was a mistake and have felt terrible guilt ever since. Is it possible to remain in what is otherwise a good relationship?

I have been in a relationship for the past six months. We are both men in our late 30s.

Early in the relationship, I discovered that my partner was using Grindr after we had agreed to delete it. He told me he was just chatting to people and then erased the app. However, three weeks ago I cheated on him with a random person I met after downloading Grindr. I have never cheated in previous relationships. That being said, I think my distrust of my partner led me to feel uncommitted and give myself permission to have a hook-up. It was quick, with me wanting it to be over as soon as it had started.

Pamela Stephenson Connolly is a US-based psychotherapist who specialises in treating sexual disorders.

If you would like advice from Pamela on sexual matters, send us a brief description of your concerns to private.lives@theguardian.com (please don’t send attachments). Each week, Pamela chooses one problem to answer, which will be published online. She regrets that she cannot enter into personal correspondence. Submissions are subject to our terms and conditions.