I think we're mostly kind of guessing here, so I'll add my thoughts. I think it's possible that he's very stressed with the move and the new job and that he suddenly reached his limit of stress that he's able to tolerate and is making changes in his life to lower his stress level.

I have actually done something very similar myself and later very much regretted ending the relationship. At the time I was drowning in stress, though, and just trying to stay afloat. It's not that you are stressful - more just the existence of a relationship, particularly a long distance one.

That's my best guess.