Why don't you weigh all the options? I see a few: -take the husband deal and be done. Your peace of mind benefits - take lawyer advice and say no. Your pocketbook benefits. And you get what is actually owed.
You have to live with this right? Earlier on you posted something about your choices being yours etc etc. pertaining to husband, but this pertains to you to and it smells ever so slightly of not wanting to rock the relationship boat.
I think you are strong enough to make the decision that is best for you alone and whether it is one or the other, you will pick what's best for you at this point in your life. Do what you want to do.
