Not sure how to move on

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181KB, 749x1155px

I met a man on a bdsm site a few years back, and we've never had an official relationship, but we have talked intimately. A year or so ago we came close to being together than we ever had been and he ended up completely leaving me on the sidelines for someone else. Not even subtly either, he sent me texts meant for her. He told me it was because of my age. I am 21, and he is 40. (He spent six months of this year chasing a 21 year old that was stringing him along and using him)
About nine months go by, and I decide we can be friends. He would flirt with me passive-aggressively, and when I would call him out on it, he would say he didn't mean anything by it.
I ended up getting a boyfriend, and he was constantly trying to get in touch with me and was more sincere with his compliments, but I got distant with him.
That boyfriend and I broke up in March.
I still have dreams about this man. He is still in my life although I am a bitch to him now. I don't understand why he still wants to talk to me.
I know that if I let my guard down around him, I will be like putty in his hands again.
How do I move on?
Or at least not imagine every guy I kiss is him?