Break up Idk if I'm doing the right thing

I been together with my boyfriend for 7 months is a very short time but its been the best 7 months of my life the reason we breaking up is because I think he still have feeling for his daughters mom they have together two kids this women is sick she went back to her country and he stayed in us with his daughter he always been helping her since we been together he used to go the hospital help her with everything I never got upset but lately they talk almost everyday and know they are friends on facebook  I'm 25 he is 36 which is a big difference I feel like this is not going anywere but I feel terrible we work in the same place everybody know we are together and I love him a lot I jut feel like I can't be with him because his kids mom is always gonna be in between we had so much plans together we were planning on moving. In together he is under my phonebill contract he has so much clothing in my house is like we live together  already I feel horrible