This is tough. Someone did this to me but had actually been thinking about things for months without mentioning it. We even were about to renew our lease on our apartment during this time, and he finally told me we needed to talk. So I agree with others, don’t make the impression things are all going well and then blindside her, but don’t start going cold either. I don’t know that I could stay neutral if I knew things were going to end in a few weeks, but the distance is probably helpful in that case.