By John Blake, CNN

(CNN) - He looked like a “red-faced pork butcher in shabby tweeds,” lived secretly with a woman for years and was so turned on by S&M that he once asked people at a party whether he could spank them.

We’re talking, of course, about C.S. Lewis, the Christian icon and author of classics such as “Mere Christianity” and “The Chronicles of Narnia.”

It’s tempting to remember Lewis only as the self-assured defender of Christianity who never met an argument he couldn't demolish. His death 50 years ago, on November 22, 1963, was overshadowed by the assassination of President John F. Kennedy. He has since become a patron saint of American evangelicals.

But the actual man whom friends called “Jack” had a “horrible” personal life, thought he had failed as a defender of Christianity and spent so much time in pubs that his publishers initially struggled selling him to a religious audience, scholars say.

“American publishers worried about offending their more puritanical readers because it seemed impossible to get a dust jacket picture of Jack without a pint or a cigarette,” says Michael Tomko, a literature professor at Villanova University in Pennsylvania.

There are three other parts of Lewis’ life that clash with his image as well:

1. His religious books made him poor

No modern Christian author sells like Lewis. The cumulative sales of his Christian books for adults - not including the Christian allegory and children's fantasy "The Chronicles of Narnia" - now approach 10 million copies, according to HarperOne publishers. “Mere Christianity” sold more than 150,000 copies over the past year alone. Perhaps the only publishing parallel to Lewis' works would be “The Lord of the Rings” trilogy, a mythology written by Lewis’ close friend and fellow Christian J.R.R. Tolkien.

But Lewis never got rich from his Christian classics, says Michael Maudlin, executive editor at HarperOne.

“His books left him poor,” Maudlin said. “He had all of this money coming in, but he didn’t take those royalties.”

Lewis vowed to donate all the money he made from his books on Christianity, Maudlin says. He got big tax bills for his Christian books but struggled to pay them because he had given the money away.

Lewis refused to renounce his vow even though his money worries persisted throughout his life, Maudlin says.

“He is a man whose number one anxiety in life was poverty,” Maudlin said. “Because his dad overspent, money was always a worry. He didn’t fix things in his home because he and his brother worried about poverty.”

Lewis’ financial worries stalked him until the end, says Alister McGrath, author of the acclaimed new book “C.S. Lewis: A Life.”

Lewis’ health began to fail near the end of his life, so he wanted to hire a private secretary to help tend to his affairs. His income, though, was so spotty that he told his potential secretary that he didn’t know whether he could pay him, McGrath writes.

Lewis was more worried about losing his teaching salary from the University of Cambridge than his book royalties, says McGrath, a professor at King's College London.

“Lewis was convinced that his books would cease to be popular and thus generate little in the way of income,” McGrath said.

2. He felt like a failure as a Christian communicator

"Brilliant" is one of the most common words used to describe Lewis. He seemed to have read everything, and he could easily write in several genres: children’s fantasy, science fiction, Christian apologetics and autobiography.

“He had an almost photographic memory,” Maudlin said. “He could recite the passage and page of a line from a book on medieval poetry.”

Lewis was not so adept in the ordinary world. He never learned to drive or type because he was too clumsy. And he was a shabby dresser who lived in a house that was falling apart.

He even began to doubt his ability to defend Christianity.

Lewis' breakthrough came as a Christian apologist, one who publicly defends and explains Christianity by invoking logic. He delivered a series of talks on Christianity for BBC radio during World War II that made him famous (you can hear some of those talks on YouTube). His fame crossed the Atlantic in 1947 when he made the cover of Time magazine.

But just as his fame peaked in the 1940s, Lewis began to doubt his persuasive powers, McGrath says.

Debating Christianity in public became “draining” for Lewis, McGrath says. At a 1945 lecture on Christian apologetics, according to McGrath, Lewis said, “Nothing is more dangerous to one’s own faith than the work of an apologist. No doctrine of that faith seems to me so spectral, so unreal as one that I have just successfully defended in a public debate.”

Lewis then lost a highly publicized debate to Elizabeth Anscombe, a young Catholic philosopher who pointed out inconsistencies in his reasoning. They clashed over passages in his book “Miracles,” which he later revised. Lewis’ confidence was shaken further when he realized that his argumentative powers had little effect on some of his closest friends and relatives, who remained hostile to Christianity, McGrath says.

Lewis thought that he had “failed as an apologist towards those who were closest to him,” McGrath writes. “How could Lewis maintain a profile as a public apologist with any integrity in the light of such private failures?”

When the BBC asked Lewis to participate in a discussion on the evidence of religious faith, he declined: “Like the old fangless snake in 'The Jungle Book,' I’ve largely lost my dialectical power.”

Some contend that even Lewis’ faith failed him.

He lost love not long after finding it late in his life: Joy Davidman was an American writer who befriended Lewis by letter and eventually became his wife. She died of cancer at 45 with Lewis at her bedside. Their love affair was depicted in the 1993 film “Shadowlands.”

Lewis had written about God and suffering in a book entitled “The Problem of Pain.” But when he wrote about losing his wife in “A Grief Observed,” he was a different man, says Ivan Strenski, a religious studies professor at the University of California, Riverside.

“The cocky self-confidence is totally destroyed,” Strenski said. “The confident, modern interpreter of Christianity is gone. He’s really a shattered Christian.”

3. He had a "horrible" personal life

When the University of St. Andrews in Scotland awarded Lewis an honorary degree in 1945, Lewis gloomily joked that he preferred getting a “case of Scotch whiskey.”

Lewis needed some escape at the time. His personal life was a wreck. The man who seemed like the embodiment of self-control and virtue in his books had a personal life complicated by dysfunction and deceit.

Lewis’ personal struggles began early. His beloved mother, Flora, died when he was 9; he never really got along with his father, Albert; and he was sent away to a miserable boarding school where a schoolmaster was literally declared insane.

“It was horrible," Maudlin said of Lewis’ personal life.

Then Lewis experienced another horror – trench warfare in World War I - but he rarely talked about the experience. Nor did he talk much about the promise he made during the war to his fellow soldier and friend Paddy Moore.

Lewis assured Moore that he would take care of his mother if Paddy didn’t survive the war. Moore was killed, and Lewis fulfilled his vow after returning home. Lewis moved in with Paddy’s mother, Janie Moore, and helped raise her daughter, Maureen.

Lewis’ relationship with Janie Moore is still mystery. Some scholars say they became lovers; others say she was more like his mother. Lewis, though, hid the relationship from his father and his colleagues at Oxford University.

“There was an attraction between the two of them from the very beginning,” said Warren Rochelle, an English professor at the University of Mary Washington in Virginia.

“When he first met her, she was 45, almost the exact age when Lewis’ mother died, and it’s clear from correspondence that they found each other attractive and engaging,” Rochelle said.

Lewis had another complicated relationship at home with his brother Warren, or “Warnie," an alcoholic who moved in with Lewis and Janie Moore. Warnie couldn’t stand her.

As Janie Moore grew older, she lapsed into dementia. The demands of caring for an alcoholic brother and a disabled woman proved so difficult for Lewis that he was hospitalized for exhaustion at one point. Yet Lewis took care of Janie Moore and her daughter even as she presumably stopped being his lover, scholars say.

“She gave him stability, a family and a mother figure,” Rochelle said. “She gave him a lover for a while, but no one can prove it.”

Lewis’ sexual proclivities also clash with the images of the reserved Englishman who touted the virtues of abstinence before marriage in “Mere Christianity.”

Lewis displayed an interest in sadomasochism during his youth. He read the writings of the Marquis de Sade; once became drunk at a party and begged people to allow him to whip them; and signed three letters to friend Arthur Greeves with the closing “lover of the whip,” according to McGrath’s biography.

Lewis befriended Greeves during childhood, and the two remained close throughout his life. Greeves was gay, but that didn’t seem to bother Lewis.

“Lewis was aware of Greeves’ homosexuality and made it clear that this would not be a problem within their friendship,” McGrath said. “He also made it clear that he didn’t share Greeves’ orientation.”

Despite Lewis' personal hardships, those who've studied him say his kindness was as impressive as his intellect.

Lewis didn’t try to hide from a public that sought his counsel after he became famous. He made no attempt to conceal his phone number. He rose at daybreak to answer letters from people seeking spiritual advice.

He even made personal visits. A priest once wrote Lewis that he didn’t know whether he believed in a loving God anymore. Lewis met the man and spent an afternoon talking to him about his problem, wrote A.N. Wilson, author of, “C.S. Lewis: A Biography.”

“The priest, who had expected the author of 'The Problem of Pain' to look pale and ethereal, was astonished by the red-faced pork butcher in shabby tweeds whom he actually encountered,” Wilson wrote.

Lewis is still surprising people 50 years later. His ability to reach people long after his death is astonishing, some say.

“It’s odd that someone has been so popular for so long,” Maudlin said. “Lewis’ books are still in front of the bookstore. We grew up with him, so we lose touch with how unusual that is.”

The Christian icon whose image we see in bookstores may first seem distant. He spoke and dressed like a prim Englishman from another time. But his life was messy, contradictory and tarnished by thwarted dreams.

Perhaps Lewis still speaks to us because we when we look closer at his life, he’s really not that unusual.

We see ourselves.