Read about this - now I've experienced it for the first time! I simply cannot believe I ever saw anything in the guy. It happened quite suddenly a couple of weeks ago - everything he did or said annoyed me. The feeling wouldn't go. I used to be very fond of him and looked forward to seeing him, and we messaged daily. The messages started to annoy me too - the same sort of stuff I used to find endearing, I began to mentally eyeroll at. I ended it today on some pretext - think he has The Ick too as he wasn't at all bothered 
Anyone here experienced this sudden turn around?