It's not about "hurt feelings," it's about the fact that half of the posts in this thread are telling this high school kid to have sex with his bandmate and then kick her to the curb. If you can't have a conversation about a female musician without reducing her to a sex object (yes, that is exactly what you're doing when you say "******* and kick her out"), you are the problem.
Grow the hell up and treat musicians like musicians, no matter what gender they are.
EDIT: To keep this post on topic: Yes, you should probably kick your guitarist out if her skill and work ethic are as bad as you say they are. Just make sure you're holding everyone in the band to the same standard.