<human>: i don't want to go into too much detail but a month ago my bf slept with someone without me knowing(semi open relationship where we are just supposed to get permission before sleeping with someone else) and then told me immediately after extremely apologetically. after a day or two we decided to try and move past it. the relationship has been long distance for a year and a half so i visited recently to try and work on our relationship and it went pretty well.

the problem is i really want to trust him again and forgive him for everything, but i'm having trouble doing it. i was hoping someone might have similar experiences or advice on how to regain that trust.
im guessing the answer is just communication and time...

i have put a lot of thought into whether or not to break up and don't want to discuss that, there isn't enough information given for that anyway. I just want help thinking of how to regain trust after such an incident.

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: my bf slept with someone then told me/apologized. we want to work it out but i don't know how to rebuild the trust we had.