I am a mother of 3 and struggling in a relationship because I am not meant to be with their father........

When I was 18, I met a man I fell deeply in love with.We married when I turned 19 and I considered thes guy my best friend.He was so attractive to me and we had so much in common. The kind of love where it was just fun to talk and play board games together. Even making love was different. Now I am back with a guy I had my first child with. Sometimes I don't know why we are even around eachother. We have nothing in common and he doesn't think the same way about things like my ex and I . We just seemed more compatible, and he accually made me a better person,while the guy Im with now and have 2 more children with at times makes me feel evil. I just feel like I accomplished more 7 years ago in my relationship with my ex than I have in the past 4 with the kid's father. I guess my question is,; What do you do when you love someone and it's been 7 years since you've heard their voice, but you still manage to think of them everyday of your life? I feel so terrible for everyone involved. Please help!!!!!