Child support/parenting time

My ex husband recently moved 2 hours away. We’ve been divorced 6 years and he has never consistently taken the kids. He pays $215 a month in child support for two kids but I get to claim both kids fully on taxes each year so I get the child tax credit for both. Our court papers also state he’s supposed to pay for half of any out of pocket medical, school or extra curricular activities and carry insurance but he doesn’t. I’ve added it up and I spend more than $200 a month on just school/child care/insurance/extra curricular activities and things like pull-ups and my daughters phone(I know that’s not a necessity but they walk home from the bus stop and her dad agreed to pay half and never did). My daughter is getting braces next year and I’m going to take a huge hit on that, insurance doesn’t cover it at all.

He’s taken my daughter to his house once since he moved and just had the kids for like 17 hours for Father’s Day. I met him halfway on Saturday then met halfway again on Sunday. He told me he’s moving in with his gf and plans to start getting them every other weekend like he’s supposed to and he expects me to meet him halfway. I spent $40 in gas this weekend just making those two trips. I have a toddler and am due again in Sept so will have a newborn and be on maternity leave only getting 60% of my income. I cannot afford it and nor do I want to making that trip twice a month. My husband says he’ll take them on the days I’m not feeling up to it if my ex wanted to front the gas money. However, my ex doesn’t want to deal with my husband and he doesn’t think he should have to front the gas money. He states it’s my responsibility to meet him halfway. I disagree, he chose to move and he continues to choose not to help anymore than what is garnished from his paychecks. My husband says to quit arguing and just file to amend the child support. After I have my baby my husband can meet him and if he doesn’t agree to that then he can make the trip here to get them. I’m technically not obligated by court orders since he lived here when we got divorced our papers state he’s to pick them up from daycare on Friday after work and then I pick them up from his moms Sunday at 5. Am I wrong for expecting him to front the money before making the trip? I told him he’d had to cash app me the gas money before we leave. Is it my responsibility to meet him? Should I just amend the child support instead? Can he really refuse to deal with my husband if he drives the kids instead of me? My kids have never really questioned why they don’t go see him. It’s normal to them and they’re not going to be upset either way.