Still Attached

I left for college at the beginning of September and the day before I left I hung out with my ex-boyfriend, that night he promised me he would call me on my birthday. Four weeks later on my birthday, do I actually receive a phone call...even a text? of course not. Even though we weren't together, it still hurt because he promised and he was still a friend that I cared a lot about. 
Now flash forward to today, and it's his birthday tomorrow. I've been thinking a lot about whether or not I will contact him. As mean as it sounds, but I want him to feel how I felt when he forgot my birthday. But at the same time, I want to text him and prove to him that I'm better then him. It's stupid because I don't even know why I'm giving this such thought. He didn't give any thought on my birthday, he completely forgot it. Even days later he still didn't remember till I reminded him. Why do I continue to care about this person who constantly treats me like crap? Why do I continue to do this to myself? Why am I still attached? Why can't I just let go?

"At some point, you have to realize that some people can stay in your heart but not in your life"