Ex help

It's been about 2 1/2 months since my ex broke up with me. He lives right down the hall from me and it's hard to see him. I know the outside view isn't what he may be feeling but he seems happy. I feel like I should just be over it but it's hard with a constant reminder. Is it a bad idea to try to talk to him? I feel like it would be but I also just wonder if he even misses me :/