I think it was Michigan, and IIRC, it wasn't adultery in general but someone living in a situation such as Michael's, where he has clearly gone on personally and has potential conflict of interest, cannot retain guardianship of his spouse. Sounds reasonable to me. Someone else pointed out yesterday that Georgia already has such a law in place. No doubt other states do as well.
The Schindlers told Michael it was time to move on with his life. They admitted this in court documents when they also admitted they knew Terri was PVS.
I think it's a ridiculous law.