It seems easier for men to do that then women. From what I've seen women can sometimes embark on an A with a "no strings attached" understanding but eventually want more. Not always, but it seems not uncommon. Men can fall in love, of course, but they can apparently have sex for years with someone with no emotional attachment.
My H claims the same thing, and I believe him. He says she did get demanding eventually as he pulled away, but he thinks it was mainly because she was lonely and desperate, not because she was in love. She did apparently yell now and then that "you're never going to leave your wife" to which he says he always replied, true. (He passed a polygraph).
Sex does tend to make people closer. But a dysfunctional relationship that includes guilt inducing sex, not so much.