This would be a problem for me too, if I were in your position. When you say he scoffs, do you mean he mocks you and blows it off? Regarding whether its normal or not, I don't know. I just know that it bothers you, he doesn't seem to care, and yes, it does seem that way that he still has feelings for his ex. Especially his reason given. I'm not sure what to tell you what to do, that's your decision if you want to live like that / have a boyfriend like that, or not. I'd consider bringing it up to him your concerns. If he scoffs, rather than comforts you, that would be a red flag in my book. How is the rest of your relationship?