And he knew. He knew you were vulnerable. Mine actually admitted it, later, when I broke the news to him that I was leaving town. He knew and, on some level, he targeted me. Like your person, I'd known him for years before. He only started paying interest in me when he found out through others that my marriage was floundering and we had separated. I fell for him like a ton of bricks. He would arrange to meet me and we'd talk and oh, what a good listener he was. Of course.
Then one night, he had arranged for us to meet nearer to his place and a restaurant/bar he knew I had to drive to.
I got far too drunk and then he said the line, 'You're far too gone to drive. Why don't you just come to mine. You can sleep on the sofa.' Yeah, right! I can't believe I fell for that.
Needless to say, I didn't sleep on the sofa.
The next day, he did the, 'This is a mistake.' I said, 'Yes.' And then he pulled me to him and kissed me and shagged me again.
I went home and was like, 'WTF?' but I didn't contact him. He wasn't long. He rang right after he got off work. 'Can you come over to talk?'
I wasn't as ill as you are and still, he was able to utterly wreck me. I let him!
We all make fools out of ourselves. But cutting you off? It's the best thing.