being a bifemale
Wow some great answers, yes every case is different, so you never know he might accept your bisexuality however:
1) are you prepared to share him with your girlfriend? or is she just for you?
2) would your girlfriend have no problem giving herself to him?
3) have you thought about your options if things go south?
4) are you financially capable of being indipendant?
5) is your girlfriend indipendant, does she have a job?