Sex with ex

So my ex and I are sorta fwb now but idk if i should continue to do this with him. For some reason I feel like I should keep my distance and such since he’s an ex but I want to also satisfy my sexual needs. I’m comfortable with him since I’ve known him for years and I’m not ready to meet someone new or arrange fwb with someone else.

I just need some advice if I’m doing something wrong or if it’s entirely up to me.