Im sorry That you are feeling this way. Im feeling sad for you. she is a truly lost soul and I don't know if she will ever come back from her alien world.
You have to do what's best at this point. Yes, your children will be hurt, but kids are smart, im sure they have an idea on what's going on.. not the details, but that something is not right.
Its been a long road for you and I wish the turnout was different. You are a wonderful person and Father and you truly don't deserve any of this.