How do you let go of somebody?

A guy used to like me, and I liked him but we started drifting apart. I realised we didn't have much in common, and our conversations were never serious and lacked substance. We don't really make much of an effort to talk to each other anymore either. A part of me kind of still wants him, but I know the best thing to do right now is to just stop thinking about what we could've been and just move on. I know I should just slowly stop talking to him, then everything he does wouldn't affect me so much but it's really difficult to cut him off, I don't want to.

What should I do? I just want to stop caring.

You're barely speaking to each other so just allow it. Part of being mature is being able to detach emotions where they're not needed.

It's just out of the guys I know, he is the one I've had the most funniest, craziest conversations with, we used to just stay up all day and night talking.. but not so much anymore. I can't see this relationship progressing any further, we don't talk long enough for either of us to really open up because he just goes to bed or whatever before I have a chance to tell him what's on my mind, which is a real shame.