[Michael's first question to Tom at the Desert Inn was “Kay know I am back?â€
]
It was over between them at that point. When Michael returned to his Tahoe home after the Desert Inn scene, Kay didn't even look up from her sewing. That's why, right after that scene, Michael asked Mama if it was possible to lose one's family.
IMO, it was all over right after the Tahoe shooting. That look Kay gives him while clutching Anthony says it all.