Yeah, the more I think about it the less I think I'd agree to a threesome like that, simpy because I detest hypocracy, and I wouldn't like her getting one over me. If she can "cheat" but you can't.... She seems to think (as many women do) that it's fine if it's the same sex... simply because it benefits them to think so.

Maybe you should start getting off with some guy, and not letting her anywhere near the action lol, see how it makes her feel.

So yeah, I'd say: "Anything you can do, I can do, if you can kiss her, so can I... blah blah."