I have to ask... WHY? And don't you think they are going to find out anyway?

There is a difference between knowledge and consent.

You can apply, but he's going to need to be informed at some point.

Legal separation is an agreement between two of you... you can't leave him out.

Legal separation is an agreement between two of you.... you can't leave him out.

Legal separation is a term its not an agreement at all. If a State allows for it and one of the parties requests it through the courts its granted. Nothing at all to agree upon as far as a separation goes.

This would also depend on your locations. In some states, there is no "legal separation".