Pence is a weasel and always has been...he’s a political Ken Doll, who looks like he’s been made of plastic to gratify the wishes of Evangelicals (even though this may not have been their wish, that’s how the GOP saw them).
They picked him because they wanted to “balance” the flamboyant Trump, and many Evangelicals were bothered by Trump’s several marriages so they picked somebody undistinguished politically but who had been married only once. Like that matters.
So they got Pence, who has felt from day one that he is morally superior to Trump and that it was his duty to work in the background to undermine his boss, which he did very effectively.
What’s worse, I think that Trump, who has notoriously bad taste in associates, actually thought Pence was on his side, at least initially. But Pence never was, he was just keeping quiet and waiting for his moment.
VP's aren't really chosen by the President.
Does anyone really believe that Reagan chose (read my lips, thousand points of light, a new world order) Bush?
Bush, with a shit eating holier than thou smirk called Reagan's plan "Voo Doo economics"...So, after we elected him to carry on the Reagan plan, the squeaky, mousey looking little bastard said "read my lips, no new taxes" he raised taxes.