OP, I was once in a very similar position to you, except the guy wasn’t in a relationship when we were ‘on’, I got strung along for years by someone very charming, very good looking, exactly my type, showered me with attention, messages, telling me he had never met anyone like me before etc etc, except there was always a reason for why we couldn’t be more then fwb, work stress, his parents marital problems ( lol), and a variety of other ridiculous excuses, he would actually get in other relationships and stop meeting with me for a while, then that relationship would end and right on cue my phone would beep with a message from him in the middle of the night, saying how much he missed me blah blah blah, and like an idiot I would jump right back into the whole thing, lapping up the tidbits of attention he was throwing me, making excuses in my own head for his behaviour, thankfully one of my friends literally staged an intervention with me and persuaded me to cut it off, I knew I had to do it anyway, it got to the stage where I was miserable and crying over his adoration one minute and then rejection and getting with others girls the next, I bitterly reject all of that time and dignity I can never get back now, I wish I had been in control right from the beginning and told him to jog on, as a previous poster has said, you need to take back control, right now he has all the control and is calling all the shots, having his cake and eating it, tell him the whole thing is over and not to contact you again, it may hurt at first but you will actually be emancipating yourself in the long run x