In essence, I think the benefit to the mono partner might be a spouse who feels happier and more complete, has a better sex drive, and is more conscious and in tune to her/his spouse's needs, and a marriage that is more consciously, thoughtfully loving through forced introspection and communication. I just don't think a mono partner is necessarily going to see or acknowledge those benefits unless he/she wants to. I'm hoping it will come in time.
But I dunno. Merely going poly doesn't mean this will happen automatically. There were times too in polyland where I felt pulled in all directions and not giving ANYONE my best.
I've actually been enjoying a deeper ORE with DH lately because we've both been more PRESENT to each other lately. And at this time we are closed. What changed was not a new lover acting like catalyst to put forth more effort in connection.
It came from putting more effort in connection!
Which has been hard in the last year given how I've been spreading my attention on to eldercare of aging parents. He gets that, and is ok with it. But in terms of energy, time management? That health stuff just brings a major DING to our home life!
I was major depleted and basically he was sucking up extra at home that I could not do because I was eldercaring. Which rendered him super depleted.
We deliberately sat down to work out needs and what could be let go and what MUST happen. The rest was greater satisfaction, then after some resting time, the reaping of rewards once mind, body, heart and souls felt topped up again and not so RUN DOWN.
I think both have it's ups and downs. Just being mono is no guarantee
of greatness or benefits. Just being poly is no guarantee
of greatness or benefits. But mono or poly... putting for some effort into the rship(s) does have potential