My ex-wife is pressing me for money, not because she needs it, not because she thinks my son needs it, but because her brain is wired to think about money first, before all else.
Two people agree to have kids and a huge shift happens in their lives and their future together. You are committing to a lifetime of connection with this person, even as you are agreeing to bring new dependants onto the planet. It's a massive transition, this becoming a parent. Deciding to divorce your co-parent is another huge shift.
I did not cause my ex-wife's anger and depression. And I'm not causing it now. And the money is not going to fix it. You can't rub money on a lifetime of depression. Sure, the new car will be nice. And, sure, she and her husband won't have to balance the checkbook as carefully.
Today I focus on my happy and well-adjusted kids. She's 50% of that parenting team. And while she still holds the loaded gun to my head financially, she's kept her mom-hat and mom-responsibility in the proper ratio.
As my kids grow older more of the divorce and reasons for the divorce will become clear to them. Life is long. Parenting is forever. Love will win out over anger.
You can't control the other parent. But you can choose your response. If you can diffuse the urgency and your need to be right, smart, witty, or even a jerk, you will go along way towards lessening the drama and making things easier for both you and your kids.