Personally, my feeling is Kay was already planning to leave Michael even before the Senate hearings. Both would've been advised by Tom that it would be beneficial for her to be there...she simply decided to appear at his side and then announce her decision after it was over (which is what she did). Remember, at this point she still loved him even though she could no longer live with him.

And as for Michael, I doubt he really considered or cared what Kay thought. He had already advised her not to ask him about his business and appearing with him would be in his eyes her wifely duty regardless of what she may have been feeling inside.

So as far as your question goes, for Kay their 'family life' was already over. For Michael, it would never have occurred to him that it was even at risk, or that these hearings would do anything to put it at risk.

Apple