Relationship help please

I need some help, or advice on where I can go to get help. I live in SW Minnesota if that gets me accurate recommendations. So I've been in my relationship for over 10 years now, we have 3 amazing kids together, and I love this man with all my heart. There have been issues, obviously there is with any relationship, I'm just having a hard time putting those in the past so it doesn't ruin what could be the future.

So when we were younger and dumber we did stupid crap. We would both talk to other people and send pictures that shouldn't have been sent. He wouldn't stop smoking pot and he knew how I felt about it because of how it affected him and his ability to care for our children. He's been clean for over 2 years now but it's so hard for me to let it go because I know how easily he could get it. He was also talking to another woman from our town 4 years ago, he swears nothing happened between them and that it was a friend messaging her from his phone as he didn't have one (I do know that this friend didn't have a phone so that's not a lie) but somehow she got my personal email, which I don't have listed anywhere and he can't ever remember my phone number let alone any email addresses, so I have no clue how she got it. She claims that they had s*x so im having a hard time putting that in the past and not thinking it could happen again with someone else. She got married and moved so she's obviously over whatever may have happened.

Because of what I thought had happened I was texting another man that was in town for a renovation job at my place of employment. I did let him see doen my shirt once and we kissed one time as I was leaving work. I told my bf about it because I felt guilty. He was clearly hurt by it but got over it. Yes I know that didn't make what I did right. It was wrong and dumb.

I will obviously never forget what happened but I'm having a hard time putting and leaving it in the past. So I guess what I'm asking for is help on how to leave it there.