Girlfriend [21F]'s best friend [21F] is getting in the way of our relationship. Anything I [20M] can do?

My girlfriend's best friend is a VERY hard person to deal with and my girlfriend always looks after her because she wants to be there for her, but I can't take it anymore. She always goes around complaining and making up problems for herself which everyone else in her life has to deal with. For example, we went to this concert and we had to leave because her friend wouldn't stop crying because my girlfriend and I looked really cute together and she feels like her boyfriend and her's relationship isn't as good. Like she sat on the ground just balling, crying. Same thing happened when we went out one night but this time is because she wasn't able to ride her horses that day. Hell, the other night my girlfriend had way too much to drink so I was taking care of her and then she just storms into her house and starts yelling and screaming for me to get out because she wants to take care of her and wouldn't stop until I left. She even sometimes comes over and tries to kick me out because she wants to lay in bed with my girlfriend because she wants attention. And now the tipping point, my girlfriend told me she was ditching our plans today that we've had planned for weeks because her best friend won't stop crying because of something she did to hurt someone else. Like I'm really fucking pissed off, is there anything I can do? I try talking to my girlfriend about it and she always says that she doesn't want to leave her alone so she doesn't do something stupid. Or do I just cut my losses and say fuck it to the whole relationship?

TL;DR: Girlfriend's best friend gets in the way of our relationship. Tried talking to her about it, nothing happens. What do I do?

Submitted October 26, 2018 at 11:01AM by eggbeaterdiskerud https://ift.tt/2O7c6EA