You couldn't know this, but that theory is like nails on a chalkboard to me, and I really prefer to avoid thinking about it. I like her storyline, to put it mildly. (Though I admit to being morbidly curious about why you think that.)

My theory is that Amy's going to be pregnant again, and that's why she'll leave. I can't figure out a way to word my reasoning so it's positive-- my brain is not cooperating right now-- but I really do think it will be.