"I wonder what OW must think" -- gee, the longer the new daddy holds out money from Alison ... the better off it will be for her and her new baby to be. He is her hero, looking out for them!
As for him denying support for the kids you share, those two lovebirds don't believe your kids are doing without. At least not because of any actions by them. Trust me. He'll let you dangle as long as you're able and if anyone is going to be made out to be the grinch - it will be you. Not letting your kids see this is your choice, and your intentions are admirable. I hope you can hang in there a little longer.