Name change because I am unsure if my ex can find me. I almost don't know where to start, so going to try to breakdown 20 years into short bits. Summarising anything too identifiable.
Marriage: ex was non-physically abusive. I even didn't realise what it was until I asked for relationship help here (I was in emotional hell and thank you MumsNet peeps for helping me see what was going on). His aggressive tactics involved things like breaking things but his real skill is psychological - guilt, manipulation, financial control (guise of budgeting), tensions, rages, gas lighting, mixed with absolute charm and generosity.
I was his stay at home wife (manipulated me out of job after baby) and made to feel like a blood-sucker on his finances. All sorts of hell went on mixed with loving behaviour. When DC1 was old enough, I wanted to go back to work. Ex spent a lot of effort guilting me into DC2. When DCs were affected by behaviour, I filed for divorce.
Ex volunteered to do DV course (realised it was just to get me back - but he hadn't changed inside, just had fine tuned his abuse to be even more sly). Ex spent months trying to persuade me to stay. Then used DV course skills to try and persuade me I was abuser (near broke me). Several years... finally got the divorce and proud I didn't have a nervous breakdown. No one would believe ex is anything but nice - it might seem silly but psychologically I am absolutely terrified of him.
Fast forward to lockdown. Ex basically wants me to take him out of Child Maintenance Services, or he has the kids more (but suggests other option 'for sake of children'). I say parent more but we're staying in CMS (because he will be controlling with finances) but I am not his wrap around childcare. He stirs up all sorts - with schedules, mind games and DC2. I was on my knees emotionally (which is what he does to win). Anyway, end result is I'm with DC1 just over 50/50 (their choice) and DC2 50/50. Ex is having a fit because he still has to pay Child Maintenance of £500 a month (he earns £2K a week). I am in the lower tax bracket, but considering forfeiting payments it because I have had enough of ex. But Ex now wants to 1) be primary carer for the kids (they'll loose child benefit) 2) says if I were to go to CMS collect and pay he would have to tell the children he can no longer afford all the lessons he takes them too because he is struggling financially.
My dilemma - I will get by with out his child maintenance, but can he take away the Child Benefit? How can he do it? Also, if I let him basically use the kids to emotionally blackmail me out of CMS (his ultimate goal), I am scared that he will do more because he'll know it works. TBH I don't even know if I have the emotional strength for dealing with him.