I would have thought her hardest day was the day she learned her husband stained an interns dress and used her for a human humidor, but that’s just me.
I recall reading reports that when Bill was governor of Arkansas they had an "open marriage" and that Hillary was having relationships with other men (maybe Vince Foster and maybe Webb Hubbell). I don't know if that is true but it would be in keeping with her utter cynicism. Of course the Monica scandal gave her the chance to play the wronged wife for sympathy.