Found a souls mate? Sounds to me like you found a douche bag about 8 months ago. Every now and then clowns like your guitarist pop up, there are however a lot of cool cats out there. My advise would be either sack the guitarist or find another band, life is too short!
My old neighbour is a concert trained pianist and joined a blues band on keyboard. He is a very good player, and like most concert musicians learns/performs the songs by site reading. He got into and argument with the bass player as this guy was adamant he was playing a bum note. Now I should mention that the bass player is blind, so he was a little naive to get Into an argument about what sounds "right" with a blind person, but so it raged for about 20 mins, and ten about another 20 later on that rehearsal. As it happens, there was a misprint in the sheet music 😳, fact is a little diplomacy goes a LONG way in a group environment!
Sounds like you already have one foot out the door, just carry on walking!! Good luck