please help me out!!

Ellie
So my bf and I have been dating for 3 months now, when we first met he had a gf and I told him I could be involved with him if he had a gf and he ended up breaking up with her. I felt very iffy about this but he reassured me by telling me how unhappy he was in his past relationship and how bad she treated him and that's why it was so easy for him to move on. We are so happy together so far and I love everything about him but every now and again I get overwhelming feelings that he will never love me as much as he loved her and I'm just here to make the transition easier for him. I have brought this up to him but he tells me he wouldn't be here if he didn't want to and he wouldn't bring me around his friends and family if he wasn't serious about this but here I am again feeling such strong feelings of doubt. I feel like the only way I will be able to get over this is if we break up for a while and let him do what he needs to do and if he still wants to be with me than I will feel better. I have also told him this but he does not want to end things. I'm just so confused about what to do. I hate feeling like this but I feel like if I being it up too often he's going to get sick of it and be done with me completely. I just need to know that if we broke up he wouldn't want to go back to his ex.