Can my ex claim that my new spouse should take place of my morning babysitter so he can eliminate his portion of child care cost

I recently got married. The current CS include child care I needed in order to go to work at 5AM. My hrs has not changed and nor has my need of a morning child care provider. My new husband has been kind enough to take my son to school when he can, but he is not a reliable morning care taker because he travels often and have early morning meetings. My babysitter is paid monthly at a small fee. I pay her on retainer so that she is available to me at a moments notice in the mornings I go to work. My ex claims that I using the child care funds as personal income. I have bank generated checks sent directly to the babysitter monthly on the days I have my son. My ex is taking me to court to get reimbursement and modification of CS. Will the judge rule his way and make me pay him back?