Shillzz, my sympathies. Oddly enough I'd just been reading the 'things that cheer you up' thread and had forgotten I was looking in this one. I now can't get it out of my head that you're actually quite chuffed.
All that said, better for her to follow her heart now, than to stay and build up resentment over a few years and then leave. Better for both of you, despite the short term pain.
Looking forward, I'd get the agreement on the house in writing ASAP; she does have a legal claim and she could come back in a while say, wanting to buy a new place and therefore wanting her bit of the house, forcing you to maybe sell up. Best sort it out while you're amicable. And try to resist the temptation to screw her over; she'll end up bitter and you WILL feel a guilt that will never go away.