They're comfortable with being a couple in my little world, but this is the first time a third person has joined them both. And that is what is bothering Fred, the change in the equilibrium and twin dynamic. Any previous extracurricular activies were out of sight, and therefore able to be dismissed.

I think it surprised George, really. He's used to them always being on the same level, and they WERE both enjoying the threesome while it was happening. Fred didn't have doubts until later.

/backstory that is all in my head, not on paper