Frankly, I'd be more alarmed if my spouse said "Well, if you can't fuck everyone you're attracted to, you'll be completely unfulfilled and forever unsatisfied in a monogamous relationship and probably cheat," than if she said she was bisexual--- but that's what you just said isn't it? It just seems... unconnected to how sexuality and partnership works, mono- or bi-.

And I'm reminded, somehow, of McKinley's Rosie talking about a stallion being put to stud: "Yes, but that's not what you do. Is it?"