Honey, if you have a "type" of lady friend that you consider hot and enjoy sex with, you are bi. You're just not a universal horn dog for all women, like some guys. There are certain types of women that don't excite me, either. That certainly does not make me gay or asexual.
Even with bi-sexual ladies who will have sex with just about any other provider, there are times when the chemistry between individuals, different sex or same, where the sparks really fly. I count myself lucky to have experienced many more of those than situations where the ladies really don't like each other and claws and fists fly (so far only one at this extreme). Someone above was right about it being better if the ladies already know each other, but I have had a lot of fun introducing my favorite providers to each other.