Why does my boyfriend always stare at his ex?

Anonymous
My boyfriend broke up with his ex 7 months ago, and we have been dating for a month now. Something has been bothering me a lot. We live in the same town, but she goes to a different school, but she lives in the same apartment complex that he does. Anyway, he always tells me how beautiful I am, and he's always commenting on my pics on Facebook; he always has his hand in my back pocket when we're at school around his friends, and he comes over to my house almost everyday after school and we text a lot. She and I are really nothing alike. I'm really thin and she's really overweight. She has a really pretty face, but he has always dated girls who were thin like me, so I really don't know what he saw in her in the first place...I don't mean to come across rude, but she just doesn't fit the type of girl he has always gone for. Here's what I don't understand. Anytime she is anywhere near us he is always staring at her. He will even purposely lag behind sometimes to try to say hello to her. She doesn't seem to still be interested in him. From what I know he doesn't text her or anything, but I've had people tell me that he will go over and try to talk to her when he sees her by her apartment. All of that bothers me, and makes me mad. I got so mad that we left a ballgame because he kept looking at her so much, even though he tried to make it not look obvious. But even all of that isn't what bothers me the most. Like I said earlier, he's always affectionate towards me at school and around his friends, but if she's around, he won't hold my hand or anything...he won't even hardly walk right next to me and he certainly won't touch me. What's up with that? I've been wondering lately if he still has feelings for her. I know one of the reasons that they broke up was because he wanted a physical relationship and she wanted to wait. Is it possible that he's only dating me because we have sex? Does he really like me? I mean if he liked her all that much wouldn't he just break up with me and go back to her? I need someone to help me understand what's going on. He swears that he doesn't have feelings for her anymore, but how can I be sure?
Why does my boyfriend always stare at his ex?
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