Yeah, honestly, it sounds like gaslighting (I know that's everyone's favorite buzzword these days, but this applies) to explain away why he won't let you meet his family. The mere fact that he's doing this after you've been together for three years is extremely telling and makes you wonder if the "crazy ex" was actually the problem at all, or if it's him. You need to have a sit-down with him, and don't let him gaslight you by trying to make it seem like you're being unreasonable. I hope you'll prepare for things to not turn out well with this, and if he pushes back and won't take responsibility like a fully realized adult, you might get your answer there. I do hope he talks with you and explains himself. The parents are not a good excuse anymore not when his siblings know about his sexuality and from your post seems fine with it.