I have let him go: I am not contacting him, barely responding to his contacts and when we do talk, I keep it light and friendly. Do I just keep at it?
Yes - I'd keep at it. You are conducting a scientific experiment here - and so far, the results indicate that when you don't always respond, he misses you and tries harder to contact you. Good things. This is making him face the reality of what he's doing, and taking some of the fun out of his new relationship (wonder how she likes it when he's fretting about why you haven't called him back?)
