This happened with my boyfriends parents.
He had so much debt when met that she always took credit cards out in her name, even though for both of them to use.
Anyway when the divorced few years ago she had �40,000 debt on all her cards. She wanted the house sale to pay it off, but my boyfriends dad turned round and said they're in your name-deal with them!
She had receipts for sofa's and kitchen brought so she was going to go to court to prove he had to pay half.
Her solictor still wasn't sure of her chances, so said best to settle out of court.
In the end my boyfriend persuaded his dad to pay �10,000 which left her with �30,000 to pay, but thought better than nothing.
So from that I would say he hasn't got a leg to stand on as in his name, but if he does decide to take you to court, then you'll have to pay for your own solicitor, so if could work out something that may be better, but does seem unfair!