I want to transfer the title of my house to my ex husband. He will pay off the mortgage with his own funds, no loan.

You have to prepare a deed from you, as the Seller, to your ex, as the Buyer. Then your ex would have the deed filed in the county clerk or county register's office. I suggest that you have the deed prepared by an attorney or title agency to make sure it's done properly. It shouldn't be expensive. However, DO NOT GIVE HIM THE DEED UNTIL YOU ARE GIVEN WRITTEN PROOF THAT THE LOAN IS PAID IN FULL.

Get an attorney to do it. That way, you can be reasonably sure it will be done correctly and, in addition, the attorney can hold the deed, the payoff, and other documents in escrow, protecting you from the deed being recorded before the payoff is done.