A good girlfriend wouldn't ask 당신 to dump your best friend... But on the other hand if she thinks there Using 당신 and she is looking out for 당신 (as in she has your back) then Listen to her! Your girlfriend should be your best friend anyways and if 당신 would pick your friend over your girlfriend then why do 당신 even want her in your life? But the decision is really up to! We (on fanpop) don't really know what's going on!!!
Your girlfriend sounds like she's jealous of 당신 spending time with your best friend. If your spending too much time with your best friend, spend 더 많이 time with your girlfriend so she won't have problems 또는 complain. I think she sounds really jealous, unless is a girl that is your best friend, that's a serious problem.
I think 당신 should take it into consideration, but if 당신 can't see a real reason, then just be 프렌즈 with whoever 당신 want and your girlfriend can't stop you.
