He wondered why he stayed with her. Just pure laziness, he guessed. He didn't want to go through the emotional turmoil of leaving her. In spite of himself he'd worry about her and it was too much trouble. He'd need another woman right away and that took a lot of talking and arguing and persuading. It was different just to lay a girl but he would need a woman around, and that was the difference. You got used to one and it was less trouble.[…]
But there was another reason too. She loved him. She really did. And he knew it. And you can't leave a thing like that. It's a structure and it has an architecture, and you can't leave it without tearing off a piece of yourself. So if you want to remain whole you stay no matter how much you may dislike staying. Juan was not a man who fooled himself very much.
John Steinbeck