My ex & I have been divorced for a decade & our daughter has decided to live with her father & step mum as its closer to her school (she’s 15)…all fine however he has now decided to apply for child maintenance. She lived with me up until now & he did contribute to her living expenses but nowhere near enough but I did not push that..I’m fuming that he’s applied as we are amicable so he could have asked. AIBU?