FWIW, Deb gave plenty of notice (not 14 months, but a couple months) to her boss, president of a local university where Deb worked as his Executive Assistant. He treated her replacement as No Big Deal. (Feeling totally unappreciated and undervalued was the biggest reason Deb was ready to retire.)

Deb trained her replacement for a couple weeks, went on vacation to Orlando with family... and after a week of the new kid handling the job alone, her replacement left with no notice.

Deb comes back to work, agrees to stay ten days beyond her retirement date. New replacement arrives. Four days turnover and Deb departs for good.

One of the senior VPs calls her in a panic. (The SVP called because Deb was in no mood to talk to her old boss.) The second replacement has also quit with no notice. Can Deb come back again? Please?

Wow, gee, sorry, can't, says Deb, I have a new job with a company nearby and I've already started. [She wanted a part-time job to ease out of working 60+ hours a week.] Buh-bye!

You situation sounds a lot like Deb's, Dennett. Leverage your position to get extra cash (as Kris suggested) or just walk away, but either way, it doesn't sound like you owe that managing partner anything.

Good luck, stick to your guns, and, as I advised my wife in her last few days, don't punch anybody in the face on your way out!