Well, I called her and told her last night. Was very straightforward about needing to move, said it was a tough decision (it was not), and that I would tell her definitive date horse will be leaving once I know from new farm.
Her response was okay, albeit predictable. Lots and lots of projection (she said she has noticed how “really unhappy I’ve been with life here lately”; when in reality her misery has made me miserable) and some blame over choices I’ve made with horse lately. But . I’m glad that moment is over. I’m sure the next month will include more barbs, but I figured that I stood the best chance of less crap tossed my way if I was businesslike and pleasant and gave adequate notice than waiting two more weeks. Toss up either way, maybe, but it’s done!