My etalks to me about his GF...

When I found out my ex was getting with the girl he cheated on me with I blocked him and stopped talking to him. It had been a bit and he randomly called me and started talking to me like how things used to be. Well for about three days he complained about the girl he’s dating (which he cheated on me with) saying he stayed with her bc of convenience, she’s too clingy, she’s crazy, and t won’t last long and he has an out if he wants one. And I told him why is he staying with her and he never gave me a good answer bc he’s putting up with a lot of drama and adding stress for just sex and it’s only gonna hurt the girl more bc she’s in love with him. it was starting to bug me bc I didn’t want to be that girl that ruins someone’s relationship (even if it’s not one I am particularly a fan of). Since she found out we were like talking again and told him that if he talked to me again he’d be single and he said that he was gonna send me a text saying he had to stop talking to me but ignore it. Well i decided i couldn’t be that girl and i wasn’t gonna talk to him and he said he respected that and he’d let me know when it was over and t wouldn’t last long. I just don’t get if he’s not telling me the truth and he really cares about her and that’s why he’s not leaving or what. I’m just super confused honestly.