I've been happily married for over 30 years - some of that monogamous and some poly and the relationship style isn't the point here. Patriarchy is the point. Yes, living together with someone else even if you dearly love them can be challenging for anyone, but 50 years ago women were second class citizens by law. They were overtly expected to put themselves last in their family and to cater to the needs of their husband. The same is not true in reverse, and the vestiges of those beliefs are still very strong. Women still do the vast majority of home, elder, and child care - even if they also work outside the home, and if they earn more than their husbands, they do an even larger percent of those things. If you also treat your wife like a sex-dispensing machine rather than a lover, on top of all those other assumptions of wifehood, it's very likely going to have a negative impact on your sex life.

How did you get off on polyamory and raising kids with multiple parents? This OP is about keeping the spark alive in your marriage by continuing to interact with each other as lovers. I gave one example of consensual non-monogamy impacting this dynamic, but it's not the point of the piece. Sure, having other partners can sometimes assist with entrenched disempowering dynamics, but it's hardly the only fix for that and not the point of this essay AT ALL.

And in many places, marriage is rare these days. My friend who lives in Quebec says almost nobody gets married any more. They have long term domestic partnerships where they live together and raise kids together without ever injecting the notion of "wife" into the mix- because it does have a subconscious impact - sometimes on the woman as well. We've all been strongly messaged about what it means to be a wife and some people want to stay partnered but don't want to deal with that baggage. I told my husband several years ago that I didn't want to be his wife any longer. I wanted to be his partner - and that's what we are, still legally hitched, but without the implied relationship hierarchy or implied wifely duties. It works well for us both.