I wasn't sure if it was fair either - just noting that people are not changing their minds as it concerns Trump.
those I have talked to that would never ever approve of adultery don't care when it comes to Trump
That's because the support for Trump has little to do with Trump and everything to do with the forces against Trump.
The people who support him are diametrically opposed, ideologically, to the people who are against Trump. This isn't some trivial "tribal" thing, like hating a rival sports franchise, although there could be an element of that. There are genuine, deep and fundamental disagreements between how "left" and "right" tribes view the world. The right tribe doesn't just disagree with, but
despises certain vocal elements within the "left" tribe, which they see as ascendant, to the point where they see those voices as an existential threat to their way of life. As Fenring noted, these groups (eg: Antifa) are numerically small, but disproportionately influential. They are absolutely a major cause of the fear driving Trump's supporters into his arms, as surely as Nazi and white supremacist supporters of Trump drive people away from him, into the arms of whoever is leading the charge against him.
Look at it this way: you're in a city that's under siege. The enemy is flinging rocks and arrows over the walls, attacking with battering rams. If the City falls, you believe (rightly or wrongly) that every man, woman or child will be slaughtered. Your king is a bastard. But he's your bastard. And the forces who want him deposed are openly working for the enemy. They're not even hiding it. They want him deposed because they want to open the gates so they can enter the City and slaughter everyone. Do you help them, even if you believe that their arguments are correct (the king is certainly a bastard, after all) or do you support your king, however immoral?
The people supporting Trump not only won't turn on him, they can't. From their point of view, doing so would be slitting their own wrists. Sure, someone like Mike Pence could take over if Trump were impeached and it's not as if it would mean Hillary Clinton would parachute into the white house - but Trump being deposed would send the message that his supporters were wrong to fight in the first place. It would be blood in the water. That is how it would be portrayed and that's how it would feel.
It wouldn't be about a specific leader's fitness or morality, but about the underlying rightness of the ideology that put him into power and a symbol of that ideology's defeat. As long as Trump being impeached is cast as a referendum on the results of the last election and on the rightness of the ideology behind his support, from the point of view of his supporters, turning on him is equivalent to surrender, permitting the barbarians to sack the city.
That's why there is literally nothing Trump could do to get his supporters to turn on him, so long as he pursues policies that put him on the correct side of the ideological divide.
I don't feel the "left" tribe would be any different if the shoe was on the other foot. There is no magic to Trump's support. It's completely understandable, and frankly, rational.