here's the thing....GF#1 as you call it KNOWS that if she drinks she turns into GF#2..who sounds like a self centered exhibitionist little hussy - treading over others feelings, picking fights, taking her clothes off, etc....but she does it ANYWAY. oh sure she apologizes....and then does it again.
free spirit is another term for someone who doesn't care how her behavior affects others. while that may sound rather bohemian, it's really plain ole disrespectful. drinking to blackout on a regular basis is a huge concern. but she does it anyway. going out to bars and getting hammered and almost getting kicked out, ticking off relatives...coming up with EXCUSES to drink 3 bottles of wine....justification, rationalization, minimizing. all classic addict behaviors.
I guess whether she has a bona fide drinking problem or not, it's a problem for YOU. and by the way, you don't have two girlfriends.....it's who she is in one body, based on the substance ingested.......I guess only you can decide if this is really the kind of relationship you want.