In terms of your girlfriend, you have to understand that each couple has 2 individuals and those individuals are pressing their ideals onto her every second they can when you are not there... I think a lot of guys have replied with the answer "You can't do anything, just live your life" because the writing is kind of on the wall here, women are social creatures, the teams are not balanced, you have an uphill battle ahead of you in terms of your girlfriends social life and honestly, one you are probably going to lose.
Its just what it is, women are so easily influenced by those around them, its a difficult situation for sure, because even when her friends are on the rocks with their relationship, they'll pretend everything is great, just to prove their point about their ideals.
If i'm jumping the gun here, somebody please check me, but this seems like a wrap.