Women to women

My fiancé at the time told me he cheated on me and got another girl pregnant. I took it heard because we were tryen to have a baby for about 2-3 yrs. after the fact that I had a miscarriage 3 yrs ago. fast forward to now the girl had the baby and I jus feel like shit like I felt like I lost everything. He calls and says that he doesn't want the girl and how he jus wants to take care of his son and I totally understand that because we both didn't have our fathers in our lives. He wants me back i started dating buh it's not working work. So I decided to take him back and see how things go and this point I don't even know if I made the right decision what do you girls think I really need some advice.