I feel you would be the better person not to reply. Simply forget about him.
Many years ago I remember a girl I was 'chasing.' It was she who cancelled several times on me. I being the always polite individual let it roll off my back. After this happening twice, she phoned me to say she was 'available' should I want to take her out on Friday night.
I 'accepted.' But by Thursday, my friends had given me an earful of what I dope I was to go out with her and that she was just using me.
I phoned her...only getting her answerphone..leaving a message that I had to cancel. I was polite but did not give an excuse. In my message I said I'd phone her later. I went out. When I came home there was a message on my phone from her, full of expletives and aggression demanding to know what reason 'I' would have in cancelling a date with her.
I phoned her back. Of course, as always, she was monitoring her calls. She didn't pick up. I apologised again, saying something had come up that I had forgotten about. I told her I had to clip my toenails on that night.
I never heard from her again.
And I'm glad.
No: be a better person. Forget about him!
go out and live!
Fr Bill