Koch, who never came out throughout his lifetime, was a popular NYC mayor throughout his three terms in office from 1978 to 1989.
Yet the New York Times shows that Koch, who later became a TV personality and political commentator, was lonely in his later years after forcing away his Harvard-educated health consultant boyfriend of many years in case it influenced his political career.
WATCH: THE AG'S RAN ON "GETTING" TRUMP
He even attempted to cover his sexuality and tackle the gay rumors which had started to swirl around him by dating the first Jewish Miss America Bess Myerson while running for office.
The pair known as "the candidate and the beauty queen" became inseparable, as they attended public events, inviting tabloid speculation regarding an imminent engagement. Koch even referred to Myerson as his "first lady" and playfully spoke of getting married at Gracie Mansion.
WATCH: THE TIMING OF TRUMP'S TRIAL, WHY NOW?
Yet behind closed doors, the "master showman with plenty of chutzpah" would drop the act and tell his closest friends how lonely he was: "I want a boyfriend," he announced.
SECURITY IN OVERDRIVE: HOME DEPOT'S UNCONVENTIONAL RESPONSE TO NEW YORK'S CRIME CRISIS
The most serious relationship in his life was with Richard W. Nathan, a 30-something Harvard-educated health care consultant, according to on-record interviews with six people who knew about the two.
Koch, who was 50 back then and early in his political aspirations to become mayor, met Nathan - who was 20 years his junior - at a potluck dinner at Koch's apartment in 1976.
Nathan, who passed in 1996, described their whirlwind romance as "something thrilling," and explained privately then, "about being courted by a powerful man."
WHO'S UP NEXT? BALTIMORE MAYOR NEXT TO PLAY IDENTITY POLITICS...
In his bid to run for Mayor, Nathan was questioned by Koch's colleagues to leave the state, fearing it would compromise his upcoming election, which led to his involvement with Bess Myerson, the first Jewish Miss America, who was called upon to crack that dilemma.
HOUSTON'S SAFETY NIGHTMARE: CRIMINALS ON A RAMPAGE AS POLICE STRUGGLE TO KEEP UP, IS YOUR CITY NEXT?
Koch's younger sister, Pat Koch Thaler announced in an interview that while the two did not discuss his sexuality, the family would have been supportive no matter what he told them, according to The New York Times.
"He didn't ask me about whether I was gay or straight or bi, and I never asked him what he was, either," Ms. Thaler, 90, stated.
ANARCHY ACROSS AMERICA: HOW DID UN NEWSLETTER FUEL ANTI-ISRAEL 4/15 AGENDA
She continued: "It wouldn't have mattered one way or the other."
Koch further grew anger from many who denounced his approach to AIDS that was an epidemic while he was in office. There was not yet a cure and the disease was killing hundreds in the city daily. Critics stated he didn't move fast enough to handle the AIDS crisis in the 1980s or tackle spiraling crime.
Discover alternative ideas that will make you think
Engage in mind bending debate
Earn points, rise in rank, have fun
