help/ advice on fixing things

So I'm 22 and my Ex is 30,we are not together now reason bc l found out while l was dating him 5 months pregnant with my Ex of an Year. So for the rest of the pregnancy we just said we would be friends bc l wanted if l can work things out between my baby daddy but l know nothing has changed and we are better off co parent....... now I want to fix things the new guy(not the baby daddy) but l just feel like l messed up big time bc l know he has been with ladies that have kid(s) but they went back to their baby daddy but l know l would never go back i just don't know how to go about and show him