Am I overreacting?

So my boyfriend was married to someone for 10 years..she cheated on him and divorced him, pretty much took him for all he had. He had to start from scratch. When we found each other, I fell in love with him very quickly. But I don't know if he loves me or if he's still in love with her. He talks a lot of trash about her, but every time we go by her house (she conveniently moved in right up the road after her divorce with the other guy), hes always looking over there, even when im sitting right next to him and can clearly see him looking. When we bumped into her while we were grocery shopping yesterday, he was really, really nice to her and actually laughing, joking with her. I don't understand it. I havent brought anything up to him yet, and i dont know if i should..but he hasn't even noticed how sad I've been..which makes me even sadder.

Am I overreacting? Be kind..