If your wife is not in the IVA her money is her own and she can sell that house and possibly use some of the money to pay off your IVA.
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk
No it's hers to do what she likes with it - as Kallis suggests perhaps she could help you with an F&F offer to end the IVA early (although your credit rating will still be damaged for the full 6 years).