Didn't want to post in AIBU as I don't feel this warrants the traffic.
My ex has downgraded! After treating me appallingly for quite some time and giving him chance after chance to step up, I finally backed out.
It now seems he has quickly found himself a rebound. Someone who seems utterly desperate, not at all his type and is obviously fully unaware of his bullshit. I won't say anything further as it could be outing.
He's since been sniffing around because, I suspect, he's missing what he had with me and realises replacing me isn't as easy as he thought.
Hasta la Vista, arsehole! 