As the deal is closed, if there is money owed on the house, the payment from your ex will pay off the balance and title will transfer with the sale.
Verify with your attorney, but the only thing you should be signing is a sales contract created by YOUR attorney.
This sounds like an attorney matter. In California the is a process called escrow in which monies are held in a trust account pending the appropriate action taken by the parties involved.
You are receiving the money, your ex receives a deed to the property without your name.
There are third parties, in your case attorneys I believe, that take the role of intermediaries.
Ask questions until you are comfortable.
The Westcott Group Real Estate Company
17 Deer Park Ave
Babylon NY 11702