LS, I don't think you should tell her. You are doing this to know your legal rights. You aren't trying to be deceitful or trying to cheat her out of anything. I think sometimes we get to caught up worrying about their feelings. I don't mean to sound whiny, but did they consult us when they changed our lives by becoming involved with OP? IMHO I think it is best to be informed before we agree to something that we may regret later.
Life's challenges are not supposed to paralyze you, they're supposed to help you discover who you are. -- Bernice Johnson Reagon