Andrew says a hypothetical scandal in which Bill Clinton is revealed to have been conducting a post-presidential affair would be very bad for Hillary Clinton:

I may not care about the personal details of a president's marriage, but, given the Clintons' history, purple state Americans may not be so sure. The story could remind them of the psychodramas of the 1990s, dramas that impeded a president's ability to govern. It could remind them of how hollowed out Hillary Clinton's psyche has had to become - for enabling her husband's foibles as the price for her own political advancement.

Meh. I'm pretty sure most people would trade the "psychodramas of the 1990s" over the present situation. Meanwhile, it's just not the case that most people see Hillary's relationship with Bill in this light. The reality of the situation is that her highest approval ratings ever all come from 1998 and 1999; people view her and her handling of the situation sympathetically. After all, I don't actually think it's particularly unusual for a married couple's relationship to be strained by infidelity and for them to stay together nonetheless.