Could it be that she has split you two intentionally? If he is constantly coming to her rescue and siding with her you can bet she knows it. Any child in that situation will take advantage of it, intentionally or not. husband is obviously not capable of seeing what is actually going on here. He is clearly not willing to get her the help she needs and deserves. Maybe the right choice, after things have calmed down, is for husband to go and for you to keep the two kids, without fostering for a while. I was a foster home developer for many years and one of the things I always told potential foster parents at the end of a recruiting meeting was, "I have kids so I work in a foster care/adoption agency. That is my way of being involved with kids in need. I've seen to much to ever bring foster children in to my home. I will not sacrifice my own children and family for someone else's. When you leave here tonight I want you to go home and spend time with YOUR kids and pray about this. Think about it, talk about it, make sure. Then if you are still interested call me and we'll start your certification process." I would also hand out pamphlets from other volunteer organizations so that they would have other options to "be involved." Many of them called back and some did not. Right now your focus needs to be on YOU and on YOUR 2 children.
My prayers are with you. Take care of YOU.
My prayers are with you. Take care of YOU.