What do i do when my friend likes the girl im getting with?

well im seeing this girl and iv been sleeping with her etc, and the other day i went to a friends party with her (we went together). as the night went on i got drunk and so did she, she was just having a friendly chat with 1 ov my good friends then they exchanged numbers. i can tell she likes him but she also likes me, iv now just seen that they have become friends on facebook what shall i do ??