An heir to the Marriott hotel fortune claims his dad forced him out of the business and then cut him out of the family’s nearly $3 billion trust — just because he got a divorce.

John Marriott III claims his dad, Bill Marriott, made the moves after he divorced his wife, Angela, in 2015 against his dad’s wishes.

The Marriott family are devout Mormons and strongly discourage divorce.

Bill Marriott also disowned his son — setting him on the path to financial ruin, according to the lawsuit filed by John in a Washington, DC, court.

John also sued his Uncle Richard because he and Bill, his brother, share control of the $2.8 billion trust established by John’s grandparents J. Willard and Alice Marriott, founders of the hotel chain.

John could not be reached for comment, but the 56-year-old former Marriott executive told Washingtonian.com, which first reported on the suit, that the situation “is really tough.”

“To sue my dad and my uncle is the last thing I want to do, and the last thing I ever expected to do,” he said.

Bill Marriott, 85, the hotel company’s executive chairman, “has tried to take away everything that I’ve earned and everything that my grandparents left for me,” John said.

The suit’s major allegation is the father and uncle have breached their fiduciary duties by denying John his rightful share of the family fortune.

But his only crime, John told the Washingtonian, was “not maintaining the image of the perfect Mormon family.”

The punishment may seem severe for a third-generation hotelier who started in the family business as a 15-year-old dishwasher.

John then climbed the corporate ladder to executive VP before exiting in 2006 — a year after he sensed his father no longer considered him worthy of the top job.

The family trust, JWM Family Enterprises, owns 24.2 million shares of Marriott International, according to regulatory filings. They are worth about $2.7 billion based on Marriott’s Tuesday close at $199.48.

The same proxy also credits chairman Bill with an additional 15.4 million shares, worth about $1.8 billion.

Marriott did not respond to The Post’s request for comment, while a spokesman for Bill and Richard Marriott told the Washingtonian that the brothers had not yet read the complaint.

When they do, they’ll see some eye-popping admissions from John, who says he contemplated suicide at age 11 and has long struggled with alcohol and drug abuse.