Unless your husband took over the mortgage in his own name, then unfortunately you were still a joint-borrower in the eyes of the mortgage lender. Unfortunately this is something that solicitors seem to ignore during divorce proceedings.(posted 7865 days ago)You are under no obligation to provide any details about your new husbands income or assets. This is just a cheap ploy on the part of the lender and their solicitors to try and frighten you into paying up.
Your solicitor has written to them saying you can't pay. Leave it at that, don't answer any more of their letters, it will just drag you into a long running battle.