I honestly don't understand people with questions like this. The solution is simple. Just be honest with her and explain your feelings. Yes, being honest is sometimes hard. Living a lie is even harder. You don't have to be rude about it. Just be open and honest about it. If you can't be honest with your partner, who can you be honest with?
Count your wins and losses and make a decision to find another girl. From your post she sounds like a girl no guy wants. Sorry its time to leave.
"How do I make my girlfriend ...."? By finding a girlfriend who is a match, rather than changing your current girlfriend. Both of you will be much happier.
If you`re miserable now, imagine how much more miserable you`ll be when you fuck around, get this chick pregnant, and are stuck with paying alimony to the proverbial prude-bitch-ya-love-to-hate; all of that because sex with her was easy to procure; and you realize it wasn`t all that different from having gone to a hooker for a blow job after all! j/k :biggrin: