I was in one of those relationships with my ex. All my friends hated him, but I refused to see what an absolute fucking nob he was. I was pretty vulnerable at the time and the fact that he "loved" me - he was ridiculously good looking - seemed to be a miracle to me. Socially not even awkward but awful, thick as two short planks, condescending to me at nearly all times, when we moved in together, he would go out for a loaf of bread or something and then not come back for five days. One of the things that stays with me, and it was such a tiny thing, was that if I was reading a book - I love to read - he would say "why are you always reading, why don't you just do something else." Er, I was doing something, I was reading a book and I wasn't always reading. He leeched off me as well.
One of the reasons I stayed was because sex. The other was because he wore me down so much that I felt grateful that someone wanted to be with me. I can't even remember exactly how we split up in the end, but I moved in with friends, go therapy and life got so much better. About a year later we bumped into each other and I had one last night with him, which was actually rather lovely, mostly because I had control of who I was again and recognising it, he was trying hard to not be who he really was. He then asked me to marry him and I laughed, not nastily, but it just seemed like the most ridiculous thing that either of us could do.
Finally met him about five years later when he apologised for how he'd been with me and I said "Thank you, but I don't need your apology. You couldn't have done what you'd done to me if I hadn't let it happen. I'll never let anything like you happen to me again."
Last year he contacted me on Facebook and when he found out I was single he told me I should think about getting married soon before "my pussy dried up". So, still the charmer. Yes, I blocked him.