I brought a house with my ex husband, he has now re married, as have I plus I have changed my name.
What rights to the house do I have?
My name is still on the mortgage and the deeds on the house.

If your name is still on the mortgage you still have an obligation to pay if he fails to.

Wasn't that issue addressed upon your divorce to him? A good lawyer would have included that in the settlement.

As long as your name remains on the deed... you retain partial ownership rights.