Alberto Del Rio is tappin' out on his day job as president of the MMA org. Combate Americas after an alleged domestic incident last week involving his WWE superstar fiancee Paige

A rep for Combate -- a promotion featuring Latin fighters -- confirms to TMZ Sports that ADR is "stepping down" from the helm of the company. 

We broke the story ... Alberto and Paige got into an altercation at an Orlando airport last Sunday. Police investigated, and have recommended that Paige face charges. Del Rio is still under investigation.

Alberto was appointed C.A. prez in October 2016 -- and once described himself as the Dana White of the company.

Now he's out of a job ... but won't have to hit the unemployment line. He's still employed by Global Force wrestling -- though he's currently suspended.

THE AIRPORT ARGUMENT
TMZSports.com