I'm sure some folks knew. I'm among the folks who knew he'd wed and divorced several times, but I didn't know he is as serial/repeat adulterer.
Then again, in my social circle, Trump was disreputable on both professional and personal levels. Indeed, when he announced, my lack of first-person contact with him is why I, unlike several folks I know, was, when I first heard the scuttlebutt that he'd run for POTUS, willing to give him a chance. The people I know and who know him predicted my sanguinity would be futile. They were right, and had I known them better, I'd have taken their word for it from the get-go...Alas, they're acquaintances, not close friends.