I got a problem with my gf's best friend cont.. III?

i could not type all in one Q so i did two Q I am sorry about my spelling for those who complaing u r right. to make it clear cristal is the one who was mad my gf was ok with me leaving I had to leave it is cristal's house my situation with my gf is complicate very complicated...I fell like cristal is jealous of me or her I am not sure she is always camplainin when i am with my gf when cristal and I r together it is just fine no problems but if it is the 3 of us it became a problem bcuz cristal said that no one cares about what she feels or wants..I am gettin tired of her crap,Yes I am & my gf has a gf so she is cheating with me and we have to see each other at cristal's house or spend time when my gf is with cristal....cristal says she is st8 so i just dont get it. IF cristal thinks that I am between her and my gf or my gf is between she and I.I am not friends with cristal just bcuz i can see my gf but i really like the girl as a friend, right now she is the one that help us