I need to cut him off

I started talking to this guy after a month and half, and he said he broken up with his girlfriend in September, like 10 months ago. Anyways he’s like when i started talking to you, i started missing her. Now he’s back with me, but he still calls me at 3 am and talks dirty and then i tell him to stop and talks normal and he’s like let’s hangout has friends and still get to know each other, but every time he sees his girl he blocks me and then unblocks me after seeing her, I’m not no side chick and i need to stop being his friend !!! It’s disrespectful to her and to me as well!