Worried about my boyfriends past

Hi all.

I have been dating my boyfriend for a few months and am falling head over heels so fast. We recently had a serious discussion about our pasts and his kind of worries me. He was with he ex girlfriend for about 13 years (they have two kids together) and he admitted to me that the first few years of their relationship he cheated on her. I asked why and he said something was always missing and he was young and dumb and didn’t break up with her even though he should have. She got pregnant with their first kid and he said things were great for a few years but after awhile he was unhappy again and realized he was only in it for the kids. He didn’t cheat on her again but remained with her for several years only for the kids and not because he was happy. He eventually broke up with her and here I am.

I’m worried about the whole “once a cheater always a cheater” thing. I know people can change. One of my best guy friends used to be an absolute dog before I met him and he opened up to me about how he just grew up and realized how wrong it was. So I know it’s possible.

This was like 10 years ago for my bf with the cheating. I don’t know what to think. I want to be with him but am scared he could do the same thing to me but also recognize people have capacity to change. I personally wouldn’t want to be passed over and not given a chance over things I’ve done in my past.. I’m not a saint either.