Struggle with my girlfriends past

Hey, I am in a relationship with this girl now for almost a year. And I struggle a lot with her past lets say. The two of us are very different, we are none alike. That is also something that can been seen in how we act and the kind of people we hang out with. I am 23 now, she is 26. She is my first girlfriend, I am her fourth boyfriend. I barely have any experience (I am talking about sex), she has a lot. I am gonna tell you somethings that I struggle with. First of all, she only hangs out with guy friends. She has a couple of female friends, but her real friends are all guys. Lets take for example her best friend. If you ask me, and also herself, their friendship is weird. They are extremely close, and if you ask me they do things together 'just' friends wouldnt do. One night we went out for karaoke, and since I would never sing that, she went to go sing with that best friend. They went to the front, chose a song, but it didnt stay with singing alone. They also started to dance, but not the way friends dance. She was grinding her ass against his private parts like you only see in movies. Her hands were all over his body. Right there, in front of everybody, in all the attention of everyone. And right in front of my eyes. That really hurt me to see her like that. I talked with her about it afterwards, she said it was just a show. Then there is this other friend. First time I met him already really disliked him. He is this hippie kind of guy, but an extreme one. Full with ugly tattoos, always under the influence of drugs and or alcohol, playing in a blues band. He has a new girl all the time, fuck buddies, nothing more. Later I found out, she used to be one of his fuck buddies. But she told me that it wasnt going anywhere, so she told him that it should stop. Now they are still friends, they out together. Go for coffee/tea, they hang out at his place where he teaches her to play some kind of instrument. I can't get this guy out of my head. I see him in my dreams, having sex with my girlfriend. In my dreams I do the most horrible things to him, things who go behind your imagination. I truly hate this guy, and I wish him all the worse. I know that that is a bad thing, but it would be a lie to deny it. One time after we went to one of his concerts, she told me after the concert: I am going to talk with the band a bit (at that point I didnt know about their history yet). She went backstage with them. When they finally came back, the two of us when to my place. Later I found out that she was smoking pot with the band. Note that I hate drugs. I was extremely mad at her, because she told me she was just going to talk with them. I was really close to break up with her, cause I dont want no girlfriend who is doing drugs. Especially not with some band, with the kind of people I really dont like, backstage. If I had known at the time about their history, I probably would have broken up with her. I have to say this: I do trust her. She says all of this is over, that I am the only one she wants to be with now. I believe her. But I really struggle with her past, how do I deal with that? I dont want to ruin the good thing we have going on now. Please help me, I need it desperately. Tim

Your GF is who she is; she won't change and you can't change her. All you can do is accept her totally. If she doesn't share your values and standards and what you deem as acceptable behavior for a relationship, then you'll be forever 'clashing' with her. Sure, she can tell you one thing but her actions tell you that she's not 'on your page'. You either accept this or you find someone else whose behavior and attitude basically mirrors yours.