She made her feelings known. If you want to get married to her and she is trying to stall with that reason, cut your loss and move on. I would. Before I get downvoted into oblivion, I admire her wanting to reestablish a relationship with someone she hasn’t seen in years, but when it affects relationships, it’s too much

Move on. That's just a lame excuse. The dad could be dead for all we know. I'm any case, he's never had any interest in her and there's no reason he'd agree to participate in her wedding even if he is located. Next!

Dump her ass

I unfortunately understand her feelings and I'm sure if I was female it'd make it even harder, but again I agree your life sucks and that shouldn't effect your relationship.

Yeah that’s a shady excuse. I’d have a deeper talk with her about it, and if nothing’s on its way to changing soon, then I’d rethink the relationship altogether. Good luck