Have you tried to just say "Ok, I don't understand completely, but if this is what you want. I'll cooperate".
Then walk away. Go out and do things for you.
I'll be honest, the whole open bi-sexual relationship shouldn't be this hard. It's like a swinging f'n door and WAY above too complicated for me. I don't get it. JMO
BUT validation goes a long way. Validate and listen. Don't try to HOLD on. Agree and accept, and move the opposite direction.