My girlfriend is anxious to introduce me to her Ex's parents/family.

[gerrythesnake]

Dump her

[Minervah]

The mods will undoubtedly move this to the relationship forum because it does not seem to have anything to do with relocation.
It does not appear that moving to another city will help the OP's situation unless it's to get away from the problem with the family but I don't think that was the intent of the OP when he posted his question.

[NilaJones]

Do you want to marry this girl? Then meet them.

Do you consider this relationship temporary? Then don't meet them, and break up soon.

These are people she is close to. Like a normal, healthy adult, she has stayed close to them even though she broke up with their son. She doesn't hold the breakup against them. You, on the other hand, with your paranoia that a year later she is stiill trying to 'show' her ex something, are acting like a little kid.