Raymond Chandler was not like his creation Philip Marlowe in most respects, except for the fact that both author and hero liked to drink. Chandler was perhaps creating the kind of man he would like to be. He describes Marlowe as being six feet tall and weighing 200 pounds, whereas Chandler himself was a relatively small man and not in the least heroic or aggressive.
Chandler married a woman who was considerably older than himself. It has been suggested that he wanted a woman who would be more like a mother to him. He was apparently consistently faithful to her, even when he got involved with writing for Hollywood and was surrounded by beautiful young women. His hero Philip Marlowe may be very attractive to women, but he is a loner and an introvert. Chandler must have felt a need to explain why Marlowe did not get married and didn't at least have a steady girlfriend or fiancee. Part of the explanation seems to be that Marlowe claims he likes the kind of women who are promiscuous and have no interest in marriage and domesticity.
When Marlowe meets Anne Riordan in Chapter 11, he immediately likes her, although she is just the opposite of a smooth, shiny girl, hardboiled and loaded with sin. He recognizes her as being a possible soul-mate. She has brains, curiosity, courage, and an independent spirit, just like himself.
I liked the cool quiet of her voice. I liked her nerve. We stood in the darkness, face to face, not saying anything for a moment.
But, characteristically, he refuses to let her help him. He tells her:
"I don't want any help. I've got to think. I want to be by myself for a while."
Chandler had created a hero who was a loner, a heavy drinker, a solitary thinker. The author didn't want to risk changing his hero's character traits. We tend to like Marlowe and to identify with him because we ourselves often feel like lonely outsiders in this world--or at least this is probably true of the people who like to read Raymond Chandler.
In Chapter 28, it would seem that Marlowe is giving some thought to establishing a permanent relationship with Anne Riordan.
"A fellow could settle down here," I said. "Move right in. Everything set for him."
"If he was that kind of fellow. And anybody wanted him to," she said."
He is only half in love with her, and she is only half in love with him. Both of them understand that a permanent relationship wouldn't work out. Marlowe will have to remain the lonely knight errant, because that is the way his creator wanted him. At the end of the series of Philip Marlowe novels, Chandler had Marlowe married off in an unfinished novel titled Poodle Springs, which was later finished and published by the famous private-eye mystery writer Robert B. Parker.
As quoted in a review by Ed McBain in The New York Times:
The whole point,'' Raymond Chandler once wrote, ''is that the detective exists complete and entire and unchanged by anything that happens, that he is, as detective, outside the story and above it, and always will be. That is why he never gets the girl, never marries, never really has any private life, except insofar as he must eat and sleep and have a place to leave his clothes.''
It seems likely that Chandler was impressed by the success of The Thin Man by Dashiell Hammett, which became a highly successful movie and was followed by many equally successful sequels starring William Powell and Myrna Loy.