How would I know if my fiance is just using me?

He is never interested in my ual needs, he only worries about that when he is in the mood himself. He never contributes money to the household, only takes and asks for more. I seldom get help with the baby, even so I can just take a bath, but he can run around whenever he feels like it. He is constantly checking out anyone younger and prettier than me, including spending the last year going to a coffee shop everyday so that he could see a young brunette who always talks to him everyday. He never says anything nice to me about how I look, even when I am in great shape and trying very hard to look my best. He's first to tell me that girl or this girl is very pretty though. I don't trust him anymore. It just feels like he is using me for my good income and my nice house. I think given the chance, he'd prefer one of the younger models, so to speak. But he swears he loves me and wants us to be together forever. What should I believe?