it can be forced with a court order, and it sounds like she is satrting the process now. What's up with either getting another mortgage on another place or renting somewhere? Even when she gets a court order, it's not like you'll have absolutely no notice and be out on the street the next day.
The truth is that the mortgage you have was only acheivable because the two of you took it out - now there is only one of you you need a smaller mortgage. Your relationship failed, she should have forced a sale at the time but for some reason didn't but now you have no relationship and no association apart from this financial one