Well, first of all let me thank you all for your replies. Like I would expected, your advices differ from one to another. Afterall, life is not black and white but shades of gray.
I've managed to get her into a "deeper" conversation last evening. I found out that she's not quite happy with her relationship and that her bf doesn't care that much anymore. This is nor good or bad ... i know from my previous relations that when you start to care less she suddenly cares more. Women are not exactly logical when it comes to love matters. I also found out that he is her first real bf (knows him since highschool) so it makes sense why she's still staying with him tough she's not happy anymore.
Someone said here to take the dive and go confess her everything. I hope you were just sarcastic. Everybody out there who dated more than 1 girl knows doing smth like that is just plain suicide.
Also, somebody else said that I idealize her. I don't, that's exactly the point. I think she's far from perfect. She has many flaws but she acts completely natural, that's what attracts me most about her.
Anyway, I've made up my mind. She's not married, she does not have kids so I'll go after her. I'll play so hard that even Clark Gable would be jealous I know i can have her if I really put my mind on it. Thx "Grayer" for the motivation.
I'll keep you posted.