We might say you are heteroflexible. Congratulations!
I'd suggest you stop talking about your desires to be sexual with a woman and just do it.
Continue to enjoy your idea of threesomes and at some point, a woman will appear who satisfies both of your requirements.
Bisexuality is a stable sexual orientation and that bisexuals are as likely as lesbian or heterosexual women to commit to long-term relationships.
Sexual orientation is very complex and doesn't happen or change "over night."
We all have a bisexual component in our sexual make-up.