I like someone that’s not my boyfriend

I really like this guy, and we had a thing going on 10 months ago. We got in a fight and haven’t talked in ages. Since then I got a boyfriend who is great and very caring. But I can’t stop thinking about this other guy. It’s so frustrating, but he won’t even talk to me. And it’s so unfair to my boyfriend that I’m not fully invested in our relationship because I’m hung up on a guy that won’t even speak to me.