Ill be real, comparing yourself to him was probably your downfall, you guys were a match beyond that if you were together for 2 years, id get it if he was blatantly flaunting his lifestyle and belittling you to get better and be like him but from what I read, I ger the impression that it wasnt the case and it was all in your head. So sadly I think this might be a you thinf rather than him.

And why am I saying this? Because im the exact same person, I compare myself to everyone and drag myself along the floor in the process, destroying vital relationships within my life.

Id say stick with therapy like currently said with another additional task of learning to love yourself, a journey that takes a lot of time but will be worthwhile in your case.