Hello. I've name changed for this.
Ex and I have been separated for a few years. We have a son. He was employed and paid x amount a month in accordance with cms guidance. We didnt go through cms legally as we didn't feel it necessary. End of last year, ex quit his job to go self employed. He didn't actually end up going SE as it fell through with one thing and another. He has a stash of savings so continued to pay for our son at x amount a month.
Since September he has found full time work which is a higher income than his previous job. Today I broached the subject as he is still paying me a flat rate of x. When I ran the new figures through the cms calculator, according to that he should be paying y (more than what he is doing).
He has said that because he continued to pay me throughout his unemployment, he shouldn't have to pay more now. Its only £30 a month more. He said he will deduct what he has paid throughout the months he wasnt working until I have squared up with him.
Is this correct? Thanks for all and any advice. Prepared to be told I'm unreasonable for asking