I understand what you are saying. I'm also married to a guy, but am clearly bisexual and always have been and continue to be. I have had an open relationship so I have had relationships with women while married. This is a bit difficult for many people to understand since open relationships I guess are thought of as a fad of the 60s or 70s. My therapist occasionally gets confused though he was a free love hippie type back in the day.

Anyway, regardless of what your therapist personally is able to understand, in professional terms therapists are required by codes of ethics to handle diversity issues. If they don't get it, it is there responsibility to figure it out, not yours.