Love-making is not indeed necessary.

The wife's latent erotic needs, while still remaining unconscious, have come nearer to the surface; now that she has grown mature and that they have been stimulated yet unsatisfied for so long, they have, unknown to herself, become insistent and sensitive to a sympathetic touch.

The friends may indeed grow into lovers, and then some sort of solution, by divorce or intrigue--scarcely however a desirable kind of solution--becomes possible.
But we are here taking the highest ground and assuming that honourable feeling, domestic affection, or a stern sense of moral duty, renders such solution unacceptable.

In due course the husband returns, and then, to her utter dismay, the wife discovers, if she has not discovered it before, that during his absence, and for the first time in her life, she has fallen in love.

She loyally confesses the situation to her husband, for whom her affection and attachment remain the same as before, for what has happened to her is the coming of a totally new kind of love and not any change in her old love.