I am selling a house in Texas. The person I was selling to said he wanted to back out so I listed it with a agent. After they found out what the new listing was for they tried to sue me to make me sell them the house. In the mean time I got married. My Q is: since I got married before the supposed closing date does my wife's name have to be on the contract to make it binding and legal?

You need to speak to a attorney, but for the deed, no, since their name is not on the deed. But many states have a form that the wife signs to show that she is aware of the sale and agrees to it. I am not sure if TX requires this. But the attorney doing the closing will know of all the forms required.

And as for as the first person, once they told you they wanted to back out, that ended the contract