Easily at least half of married men view their wives like this. They get commitment and servitude from their wife, while they treat her like a FWB, except she gets no friendship or benefits or orgasms out of it. Completely one-sided. It's way harder to pull off with a girlfriend than with a wife, honestly.
Sometimes girlfriends have higher standards than wives do. I say this as a married woman. Girlfriends tend to be younger, still learning and growing, they are more easily able to get rid of the man, they aren't legally and physically tied up with him. Even living together is not the same. Meanwhile a lot of married women are pickmes and think they've "won" for getting a title and will take all kinds of disrespect, abuse and exploitation just to keep that title.