is this selfish of him?

I decided to go separate ways for good with my kids dad.. he’s been furious since and y’all I couldn’t say the half of what i’ve been through with him.. threats and all.. well he’s an otr truck driver so I let him get the kids when he gets back EVEN THOUGH WE HAVE A COURT ORDER for visitation rights.. he moved back in with his mom since I put him out so they go over there when he is in town. I asked him to help me buy our daughter some diapers and we have 2 kids.. he told me she already had some.. I said no she doesn’t THIS MAN said “she has some for over here hold your own weight that’s not my problem for at your house” y’all i’ve been stugglimg bc my job isn’t giving me hours as it is and it’s tough.. he makes a ton of money and doesn’t want to help me with his kids so I have to buy literally everything and struggle.. he doesn’t want to help me buy them any clothes bc he doesn’t understand kids need clothes 24/7 as they grown a lot and very fast.. it’s been rough and he’s not paying any child support bc the office has not picked up that he switched jobs.. I think it’s selfish of him to do that as we both made the kids why not help me even though we are apart? like isn’t it still his legal responsibility to help me?