she probably isn't as much as a free spirit as you think, she is superficial=probably not a free spirit
Dude, no offense, but if she's that concerned about looks to the point where it interferes with your relationship, she's not worth being with. You're likely growing out of each other. She needs to start dating a guy who's more concerned about his looks than the relationship he's in, like her.
if the dude is willing to sell out who he is to satisfy a superficial bitch..........then let him, it's his life, and everyone has to make thier own mistakes.