Poor Tavs
Maybe you could try no contact for next 2 months and leave her to her own devices. Ofcourse you will loose clarity and control of the situation, but it may just give her enough time to realize her mistake and enough time to miss your company and comfort. Maybe talk to her and say you think it's time to have no word until the 6 months period you guys set out is over? Then she will have enough time to find out what its REALLY like to be without you and decide for herself if she really wants it to end this way. It's a shitty end, i know, but maybe in a new town all by herself without the support you ussually give her she will realize just how wrong she really was? But then again she might just find somebody else and move on. It's a pickle and i guess really is your call. I'd leave it at no contact and speak again in 2 months time (Just get her promise to be faithful during that time).
I really feel for you. You have a lot of strength for putting up with crap like this (I know i wouldn't). Wish you lots of luck!!!
Don't cry, don't regret and don't blame
Weak find the whip, willing find freedom
Towards the sun, carry your name
In warm hands you are given
Ask the wind for the way
Uncertainty's gone, your path will unravel
Accept all as it is and do not blame
God or the Devil
~Born to Live - Mavrik~