Hey Diss, absolutely don't reply. Also, stand firm and next time don't ask her why she chose to sleep on the futon. Just let her do it. You will get little tests from her over and over again to see if you are really letting go or not.
So do it, completely let go, thats the best advice I can give you. Actually begin to act as if you are separated and let her live her life and you focus on yours and the kids. Don't let her play games with you my friend, just move on with your life and working on you.