I can't imagine how frustrating and hurtful it is for you...but if you can just accept it for what it is and welcome them every morning and go on with your day I would. If it truly stresses you out then you are free to terminate but sometimes people just suck.
Some people are NOT forgiving and some people CANNOT admit they were in the wrong...they just pout and try to win by ignoring. Can you imagine being married to him? Are you able to help the mom out by keeping the girls? I'm sure mom has a lot of crap to put up with at home with him, finding new care is an added stress...especially when dad will likely step out of line with the new day home...that daycare provider might not be strong enough to stand up for herself and will have this dad running the show.
Maybe dad will stop pouting about his routine change and start talking nicely some day. He signed the contract, needs to abide by it, if he doesn't like it he can pout and keep it to himself. Seems like he now knows enough not to try and twist your arm to his liking...that's the best you can get from these types of people!
The best thing you can do is greet him every morning with a big smile and completely ignore the fact he is being childish...it will drive him nuts because you are SUPPOSED to give in and be uncomfortable with his behavior...that's how he's learn to get his way!