Wow.
Is he the father of all/any of your children?
If not, I'd be out of there like a rocket. OR rather, kick his arse out. Depending on who has the house in their name.
He is absolutely weird. My husband wouldn't DREAM of going off at me for buying Christmas stuff, or anything, without his "permission" or presence - unless I lashed out $100s of course, which I wouldn't do, I DO always discuss presents of that size with him first - but I can do it over the phone!
For e.g. - looking for a bike for DS1 - went to Toys'R'Us, found one, was a bit more than we'd thought to pay, so I called him on the phone and said "It's $X, is that ok? If you find a better/cheaper one on ebay, then I can always return it for a refund if it's still in the box" - no issue, bought it, brought it home.
If he had to be with me for every present purchase, I'd never get half of it done!!
He's WEIRD. Controlling, WEIRD and has spat on you several times - fuck me, WHY are you putting up with that?! I know PTSD, lack of self esteem etc. but my God, he's not a good person to have around your DC. :(