Originally Posted by NotInventedHere
as soon as the topic even remotely drifted to extra-relationship sex, she made it quite clear that she's monogamous.
I'd say you've answered your own question here. Unless you want to live like a caged animal I suggest you find someone who wants the same type of open relationship you do before you get in too deep. You'll be saving yourself, and her, a lot of grief.
My suggestion: Lay it on the line now and see what she does. You don't have external ties keeping you together like some that go down this path (kids, house, possessions). If you stay together it is for the right reasons and not because you are bound by external pressures.