He left because how he's been reacting to things lately is frightening him. He's afraid of the damage he might do if he sticks around, but doesn't
want to move out, so he's extremely confused right now (I'm trying not to make it worse). It's gonna be a while before I can trust him like I did again, though. He says he would never leave without warning me again, but... words are words. We'll see.
So now our final plan is to take the break; we decided what day it would start, how long it would last and... "visitation".

Since it was his idea, the ultimate choice is up to him. I reminded him not to be shy if he changes his mind about the arrangement.
It seemed to make him feel better when I told him I trust him, and have other ideas, but his brain is on overload (I know the sh*t out of that feeling...) and we're gonna try one thing at a time. No rush.

Knowing that he's doing this for both of our sake and not all on his lonesome makes me feel as secure as I need.