Girl, you should be livid, full on, face-melting, fire sprouting rage. You are nowhere near being angry enough.
#1 He is responsible for SUPPORTING HIS CHILDREN at 50%. This includes housing, feeding, clothing, medical, transportation, activities, and anything else for them including childcare, additional sitters and pets. Additional money at the same rate for special events and medical occurrences, education costs etcetera.
#2 You pay for more than your fair share which makes him the gold digger. And WOW, is he ever! He is stealing from his own children to whom he has an absolute duty. What a scumbag.
#3 1500 per month is only 750 per child, 18% of his TOTAL income for the support of his children PLUS his rent and other costs! Absurdly low. He is a leech.
#4 The children are 50% of the household, so you are each responsible for 25%, the remaining household costs of 50% are split based on relative incomes, 1/3 husband, 2/3 to you; 17% to 33%. Total burdens 25% + 17% for him = 42% of his income. Yours is 25% + 33% = 58%. He does NOT get to shift his financial responsibilities for his children onto you.
#5 At 100k that is 42k per year to your daughters, or 3500 per month. He is $2000 shy every single month!! 100k is 8333k per month, less 1500, is 6833; what is he doing with the rest of the money every month that should be going to support his children? His money should be 8333 per month less 3500, leaving 4833 per month to him from which he will pay his 17% for his part of the household living costs.
Your burden is 58% for support. Your tax burden splits at the same rate, and, of course, the calculations should be after taxes.
#6 He MUST pay to repair the car as his children are being transported in it and he has a responsibility to make sure they are safe. He is a terrible father.
#7 He owes you back child support.
#8 None of the previous agreements make any sense at all and are not worth revisiting as neither one of you included the full costs of the children and divided those costs appropriately.
He is shirking his duties to his children and you are letting him. Grow a spine. Your children deserve every penny.