Yeah, thats actually a good question. I'm stumped. Fortunately I don't have a girlfriend to worry about that. 
I'm afraid that if that happened, I'd probably have to kill her and the guy involved. Unfortunately, I'm what You Might call a really jealous person. This is what happens when you date women who are insanely beautiful: you become paranoid. I've considered lowering my standards to alleviate this, but I just can't bring myself to tolerate back fat. Thus, I have to walk around with a constant scowl on my face to ward off other men...
I'd honestly have zero problem with it...as long as it means she gets her tits done though lo... i would be very happy...I love the idea of guys getting off looking at my gf