Hello Jayne,
My mind keeps comparing this sonnet to the Kate Bush Song "Babooshka":
https://www.youtube.com/watch?v=6xckBwPdo1c
In Bush's song, we have a disenchanted husband who falls in love with "the other woman" who happened to be his wife all along, who had tricked him to demonstrate his disenchantment was never what appeared to be, and that she was the woman who he really loved all along, at least a version of her. Now, I am taking the main conceit in your poem is that the other woman is N when she is not feeling that well, with the difference being that he husband wants to keep on trying.
The octect is written in a plain somewhat monosyllabic iambic pentameter, but I don't think the sestet also being written in that same style works, because there is not enough poetic surprise (language, imagery, situation, figuration, metaphor, specific details, and so on) in the sestet, so the sonnet does not turn as emphatically as I think it should.
It is not that the overarching rhetorical strategy of the sestet and the sonnet as a whole bothers me that much, since it is fine if you want the dissonance of the octet to resolve to domestic tranquility by the end of the sestet, but I feel that we need a more suprising and fraught journey to get there. If you don't want to up the stakes by creating too much tension in the octect, then, for me, the sestet has to do more work.
Yeah!