The usufruct is in my opinion of little use as who is their right mind would want to continue on staying in a house where your not welcome or wanted, TIT where anything can happen to you at night or day for that matter.
I think if I was in your position, I would see a lawyer, lay the cards on the table and see what he says. If it's limited to what you can do, because she will also have a good lawyer .... then I would try to forget it and move out of there as quickly and safely as you can.
Even trying to sell the house may take years, and she will do everything to avoid a sale if it costs her assets.
Remember, what ever you try to do, she will see that you get nothing out of it .... sadly TIT , and that's what happens alot.