Aha
Sorry mate, I must have had FB on in the background! I closed up early and finished off a film.
Now that I know who you are hydra (good name actually!) i will tell you again what I told you elsewhere. Your X is abusive, you see him and he gets at you. He treated you dreadfully for a very long time (understatement) and he STILL is. He does what suits him WRT your DS, he hasn't paid proper maintenance, and only does so when it suits.
You need to disengage from this dreadful man. get someone else to do hand overs, or have someone with you so he can't say anything untoward to you. Don't allow him the space in your life to comment.
WTF is he to think he can engage with you on any kind of level playing field? He's so, very very low. You eclipse him, he knows it, which is why he fought so hard to destroy you.
You need to get onto the freedom programme or into a DV survivors group. Please go to the Drs and get some support.