I think that im about to break "girl code!" And lose my best friend.?

Ok so heres the situation: my best friend in the entier world is on a hockey team. shes the only girl and she is really close to all the guys. so the other night she was at practice and i started to text her. all her friends were asking her who she was texting, so she told them she was texting me. (and they know who i am cause i go to the games and i always text me friend.) and so one of the guys asked if he could text me and so she gave him my number. and he started texting me. and he is so sweet, and kind and funny. so we started texting a lot. and i mean a lot, from morning to night. (and this guy is my friends ex!) so i woke up and was texting him and not her, and she got all pist. and then i had to fall for the guy. i like really like him. and he is so nice. and everytime i just say his name she changes the subject immediately. and i really wanna go out with him but i dont wanna tell her because shes gonna get really mad at the thought. so heres the question..... should i ask her if i could go out with him and break the girl code, or should i forget about him because hes not worth losing my best friend in the whole world???