I wonder about Marjorie Lorne Franklin Freeman. She was a professor of economics back when vaudeville comedians were still making jokes about women having the vote, and Walter was first captivated by her sharp mind, which is not surprising: a narcissistic guy like him wouldn't waste his time on people who weren't brilliant. I do think Walter was capable of human feeling, just not much or often, and at first he probably loved Marjorie about as much as he could love anyone. Later, when she took to drink and kept getting on his case about what Jack El-Hai calls his "chronic" marital infidelity (which he denied to the last, though he wasn't fooling anyone, including his own children), whatever affection he'd initially had for her evaporated. I've read that this is the paradox of narcissism: you feel you deserve the company of the best minds and the highest achievers, but are also threatened by such people and resentful of the way they divert attention away from you. So the pattern for narcissistic people is to seek them out and then either grind them down or drive them away. I don't know enough about narcissistic personality disorder to know how true that is, but it certainly seems to fit what happened with Walter and his wife.
Marjorie was thirty-one when they married, three years older than Walter, and had begun to figure she'd never get married -- which she probably wouldn't have if she hadn't met him. She might not have ended up drinking herself to death either, but there's no knowing. And she might have become famous in her own right, without six children and a brain-mutilating husband with a roving eye to worry about.