Oh, 1.9, I guess that is a special lens you might miss. And I don't know if you will miss having your dependable shooter.
At least you aren't swindling anyone.
Maybe you can strike a deal where either of you can trade back even-steven if either has remorse. That way if it's meant to be, you'll have the Leica, and if not, at least you'll have had it for a while.