Basically whoops……….
She has 50% liability when he’s there & potentially 100% when he isn’t.
You could make her liable for a different share if you think its appropriate
Then there is the Council Tax to sort out
Annual income twenty pounds, annual expenditure nineteen nineteen and six, result happiness. Annual income twenty pounds, annual expenditure twenty pounds ought and six, result misery. The blossom is blighted, the leaf is withered, the god of day goes down upon the dreary scene, and—and in short you are for ever floored.
Wilkins Micawber, Ch12 David Copperfield
