OP, I've just read through your thread. I'm so sorry you're hurt and confused, but I do agree that you need to take this opportunity in both hands. I also think that you've been given great advice I terms of what to do next.
Also, what is easier for the kids doesn't necessarily translate to what is best. You've already said your eldest kids don't like him, which indicates to me that maybe your DH having the kids full time would not be best for them. You can do this. I know it is hard and scary, but you can do this.