Sure, that's a 4th option and it will probably work for some couples. I guess it would work if the spouse doesn't understand the gravity of the situation and learns it this way.
However, in my experience, the 4th option didn't work. You can have a forceful conversation once or twice. But after that, the logic isn't new, and the repetition becomes a negative reinforcement and gathers very negative emotional associations, resulting in sexual aversion as the experts call it. And this can happen even if the unwilling spouse actually has sex and it is done reluctantly. You have a spouse who, if they have sex, has it to shut you up.
