@jespah,
Life can be quite long, and for some it will seem even longer, being nit picked for fifty years or more. Double that and consider it 100 years of aggravation.
I'm only half kidding - your perspective on promised staying together is a little jarring to some of us older than you two are.
It seems that your girlfriend has problems that need addressing, including compulsive behavior with a phone in her hand and expectations from others about constant attention with obedience as demanded.
Don't sign up for it.
Feeling sorry for whatever her past has held that was troubling is no reason to put up with a partner who is so self involved. Your being a doormat is not good for her mental health either.