To someone who I dated last summer (2017). He had a really profound negative impact on me. I was reeling from trauma from a very short relationship from 2016, and I was also dealing with an episode of major depressive disorder. I jumped into dating him and he was lukewarm at best, completely unavailable and dating multiple women at worst. We were never exclusive. Though in my pain and blindness, I expressed I wanted to be. We had good sexual chemistry. Anyway, I've changed a lot since then, and grown, etc. I still have issues relationship wise / attraction wise, but I am noticing, and dealing with that, when they arise. I think it's a good idea to write a closure letter, if need be (I'm going to pause, and wait a few days though first, to see if I change my mind). I find myself thinking about this guy a lot, especially lately. But its like he's become a part of my psyche. A symbol of very low self esteem. I already made a fool out of myself with him. I don't see how this (letter) will make it worse, to be honest.