You can "move on" and still be a civilised person, unless the ONLY thing you ever saw in the ex was sex. I like my wife as a person, not just someone I once had sex with. She's kind, funny, intelligent, a good friend. She's also now living with someone else, that she left me for. I'm managing not to be a super arse over it ( so far) Lol, and she and her new bloke are coming for dinner on Tuesday prior to picking the kids up to take them back to the States where they now live.
As I said you can move on and still act like a an adult. If this boyfriend of Catmonkey's is for her, no amount of angling from anyone will change that, so the controlling dramatics are unnecessary.