I met a girl in a dance course in October and we became very good friends very quickly and I got a crush on her.

We talked a lot and found out we had very similar life plans for things like family, home, etc. This got me pretty excited so I asked her if she was single. It turned out she was not, but still she wanted to hang out with me. It also turned out she is going for a student exchange starting in February. We started training new dance moves together even outside the course and also to cook and play board games. We started to meet 2-3 times per week and have done so for the last 3 months.

  
For me it was quite weird that she wanted to hang out with me so much so I asked her if she was into me in December. She answered that if she wasn't in a relationship she would maybe like to be with me. I also asked her if his BF is OK with us meeting so often. She said that she doesn't know what he thinks about it and that she doesn't want hurt him, but she doesn't want that her relationship limits her life either. I said to her that I would not accept that my GF met some guy many times a week. The answer of she maybe being with me was also quite frustrating.

  
We have kept on meeting and I am quite happy with the situation even though she is still in a relationship. I get a good friend who likes similar things, cooks great food and dancing is great fun. Still it is pretty clear that we also have romantic interest in each other even though we don't hug or do anything else romantic as I want to appreciate her relationship. I asked her about our situation again and she admitted that she has a personal crisis on whether or not she is in the right relationship. I said to her that if she really wants to be with her BF she should not hang out with me.  


Last Sunday I met her again and it is now pretty clear to me that she is going to break up before going on exchange. I feel kind of bad for her BF because I kind of guessed that I am going to cause them to break up and our friendship is more than just friendship. I am stealing his woman, but she always wants to meet me too and often asks me to come over. I invited her to party with me and this week we are also going to get drunk together which is going to be fun!   


Am I the asshole for actively asking her out and meeting up with her which I know is going to cause her to probably break up or is it her responsibility to take care of her own relationship?