Next time you talk to him on the phone, tell him you have another call coming in from your lawyer.
I don’t think that matters much anymore and most would probably call your bluff. Then go through a reorganization, due to rampant inflation, and eliminate that position.
At this point, wear the mask, unless you have something else to fall back on that keeps the money flowing and you happy.
No tell him you have a call from a competitor. Let his his imagination do the rest.