Have you ever pulled your friends aside individually and told them, you don't appreciate the gay jokes and tell them how it makes you feel. If they are good friends, they would accept that. If they don't then, there you have it. I know about bringing the gf around you friends and having her flirt with them. It's really hard being affraid of losing a girl especially to a friend. I've walked in on my best friend having sex with a girl I had just began dating. You know what though, her flirting doesn't necessarily mean she wants to sleep with your friends. Maybe it's just becaus she likes you and she wants to get to know your friends. I guess it depends on what kind of flirting. Right now your learning about whether or not she can be trusted. Perhaps It would help to tell her how you feel as well.
Truth is the very reason we strive to live. It surrounds and resides within us. Accepting the truths we already know and seeking out those we do not is a direct path to inner balance and joy. For life is not a means to an end, but a journey. Life comes and goes but the truth will always live on.