My ex boyfriend

My ex is annoying as hell. When we were together all he did was cheat on me. So when I found out I broke it off and moved on. I'm now in a four year relationship with the best guy ever. But my ex is always texting me. He has weird strips of time like months pass and blip! A text from him. And it's usually at an awkward time like when I'm being intimate with my current. Idk what to do I block his number but he's always getting a new phone.