Children's father returns them in poor condition, how can I (amicably) put an end to the carelessness? Co-parenting advice is needed.

I will attempt to provide a condensed image of our circumstances for context:Children, ages 5 and 10.Me, F33 and their father, M38, were married for almost 10 years. I became the martyr wife, turned stay-at-home mother who gave up school, career, everything to support him, his career, raise our children. When I was pregnant with the second child, he started acting strange, didn't come home and when he did, he wouldn't sleep in bed. The next year was even more challenging. I tried to be "the good wife" and forgive him but three years ago, he up and left completely. In exchange for "no nonsense" and the freedom for him to pursue a new relationship, he signed over custody and agreed to a generous alimony and child support. I stumbled into the world with no completed education and suddenly no husband.In the last three years, I've been parenting alone with scattered and few attempts by him to be involved. Despite my heartache, practical struggles and learning how to function I refused to allow myself to talk badly about him to our girls. They love him, when he comes around, it's better than Christmas. I grew up without a father and I don't want them to not have him, even though at times inside I wish he'd go away forever.Recently I've got him on board with having them over at his apartment twice a month for a sleepover. It's been rocky. He's got a new girlfriend and he's trying to impress her so he's upping his effort...except not really doing a great job. When the girls come back they're filthy, their hair matted, they've been fed junkfood, allowed every single excess possible. This past weekend, they came back so badly sunburned that they're blistered and in a lot of pain. I had to cut some hair off of my youngest to get her hair back to normal looking. He's basically walking all over me like when we were married, making me handle the hard parts, the laundry from the visit, the disaster state they're in. It needs to end.I don't want to fight with him. I want my girls to have their father, but holy shit his visits are an absolute dumpster fire for me. It takes me literal days to get them back on track after they visit. I need some tools and advice on how I can address this without it exploding. I've tried to bring it up with him in the past and he laughs it off.TL;DR: Ex-husband takes advantage of my kindness and leaves our daughters in terrible condition when he visits with them. I want him in their lives but I don't want to have to pick up the pieces every damn time he does. How can I set this straight? via /r/Parenting https://ift.tt/2RRLdrB