Should I leave him??

Hi loves!!

So my boyfriend treats me very, very well. But I found out at the beginning of our relationship he was a lot more rocky than I was. He was talking to other girls and still meeting up with this girl he had just gotten out of a relationship with (who thought she had another chance), even though I was being loyal and he said he was too. He said he was being immature and insecure and stupid and regrets it and was fuelled by this fear that I was going to leave him because I had left him for my ex the first time he courted me (this is true...) and thought I was using him as a rebound. He said he didn’t feel comfortable admitting to it later on whenever I asked, because he thought I would leave him and I wasn’t understanding about his past & body count (this is also true). Another thing that had me suspicious is a month into dating him I was diagnosed with chlamydia, but I dontknow if he just had that already (like he didn’t cheat he just had it from before), or if my ex had it considering my ex would always complain about a burning down there and refused to have sex with me towards the end of our relationship.

My boyfriend now is very consistent, we use eachother‘s phones all the time, he deleted Instagram because I expressed my distaste for social media, he apologized to me countless times, offered to get my name tattooed, was crying, etc. Should I forgive him and move past this? I would appreciate any advice!!!