Why can't I get over this prick?

Mr. Ex and I dated for almost three years. He used to be a real gentleman, a true romantic. We began dating in our senior year of college when our parents were still paying our rent and we had little to worry about. We both received a bachelor’s in music from a prestigious (aka very EXPENSIVE) school. His grandparents funded his education, I borrowed most of my education money on student loans.

We were crazy about each other. Both of us always said, if everything goes wrong, at least we have each other. And it was true. He was madly in love with me, and me with him. We both discussed marriage, children, building a life and our careers together, and we both became very involved with eachother’s families. His parents practically became my parents, and my nephews called him “uncle Mr. Ex”

Let me add in here that I am 27 and he is 23. Maybe that says it all and answers all of my questions.

About a year ago, he decided to take a spontaneous trip to Israel for two weeks. My priority was to diligently save up for a place together and pay my bills. Well he didn’t have any of those responsibilities except food on the table and maybe the rent. And even if he couldn’t make rent, his parents would always come in for a save, so taking a spontaneous trip to Israel was never an issue. I was jealous of this freedom.

On top of that, when he came back from the trip, pictures surfaced of him cuddling with a girl in almost every photo. I’m talking, her hands on his thighs sort of cuddling. He insisted nothing happened, but I still broke it off for about a month but then eventually let him back in because of his romanticism. And we always had a good time together. Great sex, great conversation, basically great lushes together.

The long and short of it is this.

He continued to make, what I deemed, poor financial, business and personal decisions. We would argue over them constantly. And yet I still found myself greatly in love with this guy because, well, I guess because he and I got along nicely and really loved each other. But practically speaking? Forget about it.

I continued to believe he would change and mature. What a dumb thought.

It was a rocky road to the end. He started hanging around with his female roommate exclusively. I didn’t think anything of it at first because I was also friends with her. But all of the sudden both of them said they preferred to hang out without me because they “chilled harder”. One day I woke up and she was roaming around the kitchen with her thong on. I was like that’s it, I’m done.

Broke up with him as he was leaving to take another trip, said we needed space and we could discuss it upon his return. When he returned, he said he had screwed someone else while on the road.

My question is…. Why can’t I get over this prick?