New Jersey – Jim McGreevey shockingly admits that before he became governor of New Jersey, he’d have anonymous gay sex at Garden State highway rest stops.

“All I knew was that my behavior was getting crazier and crazier,” McGreevey says of his torrid truck-stop trysts in an upcoming book that details his tortured life of lies and sexual repression.

“With each new encounter, I was getting nearer and nearer to being caught – which surely would have generated headlines, especially after I became executive director of the state parole board” in the mid-1980s.

“The closet starves a man, and when he gets a chance he gorges till it sickens him,” he writes in his book, titled “The Confession.”

McGreevey revealed to The Post that he spent time in a psychiatric hospital at an Episcopalian monastery in the Hudson Valley after his stunning resignation as governor in 2004.

And he describes in the book his fruitless attempts to conquer or hide his homosexuality by ogling Playboy centerfolds, frequenting strip clubs and becoming “as avid a womanizer as anybody else on the New Jersey political scene.”

“The more the rumors circulated, the more public and brazen I became about my heterosexual conquests,” the twice-married father-of-two writes.

All that came to naught when he resigned amid rumors of an affair with a male appointee, Golan Cipel. He then declared proudly, “I am a gay American,”

His wife, Dina, and his parents stood at his side.

His turgidly written tale, whose subject matter sometimes seems better suited to a sleazy dime-store paperback than to a former governor’s memoir, is due to be published next fall by Regan Books.

Excerpts from the tome – for which McGreevey reportedly will be paid up to $500,000 – were printed yesterday by The Star-Ledger of Newark after the newspaper obtained them at a publishing-industry convention in Washington.

McGreevey, who is now separated from Dina, currently lives with his boyfriend, financial adviser Mark O’Donnell.

McGreevey writes that he was aware he was gay at a young age. While his parents’ working-class Irish-Catholic identity comforted him, he knew “deep down . . . that this American ideal excluded me.”

At one point, he told The Post, he considered entering the Catholic priesthood because he hoped its vow of chastity would solve the dilemma.

He also writes that while he had a “great number of heterosexual experiences” while attending St. Joseph’s all boys high school in Metuchen, “I can’t say I was interested in girls sexually.”

“Yet I liked the physical contact, craved it even,” McGreevey writes.

In 1983, while attending a political conference in Atlantic City that was rife with sexual pick-ups, McGreevey got soused in an Irish pub and had an epiphany.

“I knew I would have to lie for the rest of my life – and I knew I was capable of it. The knowledge gave me a feeling of terrible power,” he writes.

McGreevey felt such shame, he writes, that he “split in two” – living on the one hand a life “that stands for tradition and values and America,” and another life that he pretended to ignore as “something spoiled, something disgusting.”

But that duality only made his problem worse, and also made his forays into the world of illicit sex more risky and degrading.

“In my case it went from the simple passions of a young adult – for physical and romantic love and happiness – to a particularly rank, unfulfilling variety of lust. I felt it get ranker and less fulfilling with each passing year,” he writes.

McGreevey longed to have a healthy relationship with another man, “with someone I love,” whom he could kiss, hug and with whom he could plan a life together.

“I used to make long lists of guys I had crushes on, scribbling their names like a teenager,” he writes. “But I never allowed my conquests to be anything like that.

“As glorious and meaningful as it would have been to have a loving and sound sexual experience with another man, I knew I had to undo my happiness step by step as I began chasing my dream of a public career and the kind of ‘acceptable’ life that went with it.

“So instead, I settled for the detached anonymity of the bookstores and rest stops – a compromise, but one that was wholly unfulfilling and morally unsatisfactory.”