Ok big edit since people are focusing on things that doesn't really matter to my problem.

My ex and I were together for 14 months and we broke up for various reasons. We were broken up for around a month and during that time, he had a one night stand. He came back to me last Friday, said he missed me and love me so we agreed to try again. I stupidly asked too many questions and now I know too much and I can't stop picturing them having sex in my head and it's driving me nuts. Every thing else is going great between us so far and I don't want to fuck it up. Any advice?

Edit: Please know that I'm not trying to make him look like the bad guy. I know he had every right to do so. I just want tips and tricks on how to stop thinking and picturing them having sex.
user
Boyfriend slept with someone while we were broken up, I
assistant
Ok big edit since people are focusing on things that doesn't really matter to my problem.

My ex and I were together for 14 months and we broke up for various reasons. We were broken up for around a month and during that time, he had a one night stand. He came back to me last Friday, said he missed me and love me so we agreed to try again. I stupidly asked too many questions and now I know too much and I can't stop picturing them having sex in my head and it's driving me nuts. Every thing else is going great between us so far and I don't want to fuck it up. Any advice?

Edit: Please know that I'm not trying to make him look like the bad guy. I know he had every right to do so. I just want tips and tricks on how to stop thinking and picturing them having sex.
user
Thinking about my ex having sex with another girl and
assistant