I miss him but I don't know why!

I was with my N for only a year and a half. Its been a year and 2 mo since we broke up. He had hoovered me, it seemed every few months. Last time I saw him was in January, when he was going through a stalking faze.

Actually, the last time I saw him was at a distance somewhere around the end of March, but that wasnt either one of our faults. We didnt speak to each other though, I just waved and walked away.

He was so cold to me when we were a so-called couple. My gosh was he ever selfish and snide with me. I haven't missed him very much, if at all, for months now until I went out with another man a few times (about a month ago), started really liking that guy, then the guy being slightly disrespectful to me and suddenly stopping contact for no reason. Thats when I started to miss my ex and have been missing him ever since. Can anyone make sense of this?