How did you get on LiverLadyLass?
Your H is undermining you as a partner, and as a parent.
This dynamic of teaching your son to play you off against his dad is warped. and sadly all too typical.
You will end up being abused by the pair of them. 
BTW, this thread has reminded me of the time that I was totally dependent on my now ex. Miles from civilisation, but only 3 floors up and a phonecall from a shop that delivers.
I asked Ex for conditioner. 2 days running. On the third, I ran out. He told me that women in his country didn't use conditioner, so I could too.
I lost a lot of hair that day, and even more respect for him. I spent yesterday afternoon battling tears at the reminder. My heart bled for you, it really did. FWIW, when others were looking he was positively LAVISH with me sometimes, but it was not for my benefit, it was for his image.
A man who would waste money on a quad bike, but not find a few quid for some knickers etc is a VERY nasty man indeed. How much does he think of you that you can't get some pants FGS?
This 'man' IS teaching your son to side with him is not a parent, he's not a partner, he's an enemy.
I know you are not ready to hear this and still naively think that you have any power to fix this, but his choices are what is driving this situation and he will NEVER give that up.
He's sensed a change in you, that's why the change of heart on the wallet.
Please love, open your eyes? You SHOULD know the family finances, you should have equal say in things to do with your family and he should be backing you up with your DS, not undoing everything you do.