I've been there. Eventually I walked completely away as I was having a convo with him one time in the phone and he said 'you sound very confident' (i had had some good news) - and it dawned in me that he wasnt happy for me. And that he never would be. That he wanted me to be down in the dumps and what he was thinking was 'oh crap, I'm going to have to work harder to bring her back down again'. It was as if I could hear the cogs in his brain thinking it.
He used to always compare me to his ex and had started to do the same in recent years with a new girl friend he had.
I ended it right there. Didn't even break up, just deleted and blocked his number. Luckily I was in a different city at the time for college.
Heres the thing, he will never be happy with anyone. They are never happy with what they have. They are always looking at someone else. Or even something else.
I caught up with him years later and he was married and in america - he always used to go on and in about wanting to stay there (again, triangulation. Meaning 'being here with you usnt enough'). And not happy.
A few month later he had moved home ('for a bit') but was still with her. And insisted on telling me how pally his wife was with the girl he had been chatting up at the time I left him (aye pal,i bet they are best friends xD). Again, an attempt at making me feel jealousy it like I was the one with the problem for not being ok with him constantly bigging up this other girl.
It isnt about you. It isnt about her.
They arent capable of being happy with anyone.
I see him local from time to time. And his words are like water off a ducks back to me now. Tbh I feel a but sorry for him. But I do so, from a distance xD
He is trying to create competition between you and this woman in order to make himself seem the prize. He isnt a prize. He is a shit in a box. Get shot of him asap. Once you've had some time and space you will see things clearly and be glad you got free.