You didn't go wrong, he went wrong. He had no right to be acting like that towards you, let alone over a political dispute. You can't physically assault someone for simply disagreeing with your opinion. Trump has created a political climate in which lower and lower forms of behavior have become acceptable and his supporters have become stubbornly and aggressively insular.

It sounds like he was a right-wing conspiracy nutter for awhile, but went off the rails after Trump got elected. He is putting his (false) beliefs ahead of everything else in his life, including your marriage. You are going to find it very hard to get through to him, because conspiracy theorists will disqualify (at least in their minds) any evidence to the contrary. This is filling a psychological need he has and is taking over him.