Can half of the mortgage payment be considered as child support? Ex-husband has told CSA ( child support agency) that he considers, that while the house he is living in is on the market, his share of the mortgage payment is for child support, while his wife is paying mortgage, school fees, medical expenses, rates, telephone, etc. That is blatantly unfair. He is using every cunning trick he can come up with to avoid paying what he owes. Please help. Thank you.