This man has not paid mainainance to this woman because the house was suppossed to be handed over to her so he didn't have to pay a bean. Now he wants half the house.
All i can say is that he is a money grabbing pig and should stay well clear. God, what else does he want.
I hope he takes it to court - gets nothing and has to pay charges, because that is what will happen when the original maintainance papers come though - so leave alone and get on with your life - grabbers.