Should I get in contact with my ex?

We broke up a year ago and I'm totally over him, the thought of being with him is really offputting. It was kind of a mutual break up but it was his fault. He text me a couple of months ago because we bumped into eachother and I replied but in the end stopped because I couldn't really be bothered. Recently I feel like I don't want things to end that way and I would quite like to apologise for not replying and explain why I didn't - but I definitely am not trying to open the door on the relationship again (thats kind of why I stopped replying because I felt like that's what he wanted).

We did have a really good relationship while it lasted and at the time he was important to me and I feel uncomfortable with that being our last contact. I don't have him on social media either.

Would it be weird to contact him out of the blue? Would it look like I wanted something from him romantically?