Dark sides of poly

A friend of mine recently returned to monogamy, after spending a couple-ish years practicing non-monogamy. Despite significant effort and support leveraged during (including many conversations with me), overall the relationship style worked very poorly for him (his experience was similar to Why I think polyamory is net negative for most people who try it). 

A few weeks later a poly friend challenged me at lunch to "steelman" my friend and I's consensus about the dark sides of non-monogamy. Since non-monogamy is a broad umbrella, I narrowed my claims to unmarried heterosexual folks practicing solo poly (UHFPSP; which describes a substantial chunk of the bay area non-monogamy community I'm familiar with), and articulated three dark sides, when compared to conventional monogamy. 

First, I think UHFPSP does worse than conventional monogamy at providing enduring support when a person acquires a disability or significant financial setback. 

I'll begin by claiming that the majority of monogamy-practicing folks in the primary 50 dating years (roughly between ages 20-70) spend a significant portion of those years with a cohabitating partner, often a spouse. The default expectations in those arrangements is for B to support A when A acquires a disability or significant financial setback. By comparison, the default expectations in UHFPSP is for A to support A when A acquires a disability or significant financial setback. 

I've seen this play out in the UHFPSP when someone was injured, once when someone died, once when someone was laid off and almost lost their home, and once when someone experienced a significant theft. Yes, friends and lovers help out initially, much as friends and neighbors do when someone experiences a significant setback; but the "family" expectation of being there for the person 6 months and 18 months and 72 months later was not there- because the expectation is for UHFPSP to insure themselves against such setbacks, since there's no reciprocal commitment to the enduring heavier "in sickness and in health" norm more present in the conventional monogamy world. Illustrations:

• For the person who died, the answer to the question of who buries you and plans the funeral, was some relative from hundreds of miles away: instead of a partner from their week-to-week life
• For the laid off person, friends chipped in two and three digit amounts against a five-digit need
• For the injured person, their non-cohabitating partner drove them to appointments for a few weeks, then tapered off their support (the injuree turned to neighbors and a relative) 

Second, UHFPSP does worse than conventional monogamy at providing relationships to the bottom status quartile of men. 

In both UHFPSP and conventional monogamy, women attract abundant potential mates (just ask any woman who's hopped on a dating app). For men, the reality is quite different. Typically their dating market power is a factor of status, and in the UHFPSP world the higher status males can have multiple partners. True, the women can as well, but in my observation women desire on average fewer partners than the average male desires. You can see this by comparing partner counts between women (who generally have the number of partners they desire, given the excess supply) and high status males (who also generally have the number of partners they desire, by contrast to their low status counterparts). High status males usually have 3-4 partners, whereas women usually have 1-2.  

The mathematical result at the population level is a large group of low status males with fewer relationships/partners than they want. Often, these men go for significant periods with zero partners. By contrast, because monogamy pairings are 1:1 and match the gender split, at the population level low status males have a higher chance of having at least one partner. 

There are also a few exacerbating factors.

1. Bisexuality. In conventionally monogamous populations, women are expected to be fully or primarily heterosexual, and because of the single partner expectation, are far less likely to experiment with or have a female partner instead of or in addition to a male one. In UHFPSP circles women, much more than men, experiment with and sometimes have female partners in addition to their male ones - which results in the low-status males competing against other women in addition to the higher-status males, further amplifying their undesired relationship scarcity. 
2. The slightly higher male:female ratio of UHFPSP
3. The higher ratio of attraction to women in the trans woman population, compared to trans men 

Third, UHFPSP only "works well" for folks at a narrow intersection of traits:

1. Attachment needs are met by the relationship model (for many folks, jealousy and insecurity leave them feeling more anxious and stressed than in monogamy)
2. (if male) don't believe in the "valley of the dolls"
3. Desire the multiple partner or autonomy aspects of UHFPSP
4. Competitive in the dating market

I happen to fit all four, which is mostly down to luck, and is why I'm staying put in UHFPSP. However, I know three folks where #1 wasn't the case for them: all three of them left UHFPSP. I know two women for whom #3 faded, and they too transitioned to monogamy. Then I know a whole lot of frustrated men who ran afoul of #2 and #4, some of whom gave up and returned to monogamy and others who are still trying. 

(Valley of the dolls is the widespread fantasy among men that, without the strictures of monogamy, they can finally have what they deeply desire: low-effort casual sex with lots of attractive women. It usually only takes a few hundred of the "no ONS" and "no hookups" reminders on every other woman's dating profile on apps, and a few dozen failed attempts, to disabuse the notion that supply exists to meet this demand- but it's a compelling fantasy, partially rooted in evolutionary selection pressure, and many men have a hard time letting it go despite the lorries of evidence.) 

Conclusion:
At the individual and group level, there are dark sides to at least some poly cohorts!