Until cis-het men let go of patriarchal ideology and the limits it sets regarding sex & sexual pleasure, don't hurt yourselves.
The story starts out the same: a cis-hetero man gets bored with his monogamous relationship with a cis-hetero woman and suggests spicing up their relationship, either via swinging or jumping into an open relationship. The cishet woman is sometimes hesitant to try but ends up agreeing to these new boundaries with her husband. Then, something happens that makes the husband question his spicy idea: either he witnesses the wife actually being sexually pleasured by other men, or in the case of open relationships, the wife has more luck in the casual sex pool than the husband. The husband starts having second thoughts about this new arrangement; he becomes insecure, and even jealous to the point of resentful of the wife because of whatever events that have slighted his ego.
And then we get goodies like THESE popping up on the internet.
Why do these men keep running into these walls head first and ruining their lives?
Because they, like most people, jumped into the waters of ethical nonmonogamy, waters they've never learned to swim in. Too many cis-hetero men assume swinging or open relationships are easy because they're often mainly thinking about their own sexual wants, standard behavior taught to all by patriarchal ideology. So they jump into ethical nonmonogamy thinking they'll have their cake and eat it too without repercussions, only the repercussions show up in different ways and show how ill-equipped they are, and the cake turns into a lie.
So, what IS IT?
Basically, ethical nonmonogamy is an umbrella term for varied types of sexual and romantic arrangements and pairings that don't adhere to the main element of monogamy: being with only one person at a time, whether for casual hookups or for long term pair bondings. Examples of ethical nonmonogamy groupings and behaviors include swinging, polyamory, polyfidelity, group sex, extramarital sex, group marriages, and open relationships.
The main and important element to remember about ethical nonmonogamy is that it cannot be equated to infidelity because all parties involved MUST enter into it consensually, hence "ethical". All parties involved are aware, open, and honest about their wants, needs, insecurities, primary partnerships, and obligations, etc. These are elements that cis-hetero men, in general, do not provide in their monogamous relationships because they are the antithesis of the patriarchal ideology they've lived their lives by and adhere to when performing manhood. In thinking nonmonogamy is somehow easier and would allow them access to more women's bodies and sexual labor, their relationship flaws show up more pronounced and they set themselves up for failure when embarking on any nonmonogamous arrangement.
Patriarchal ideology teaches men that women are possessions to be acquired, and when it comes to sex, no other man should be able to sexually satisfy that man's possession. Women are not seen as full human beings with our own sexual needs and desires to be considered and catered to, and whatever desire we may have MUST be satiated by the man we're partnered with. So, of course, when cis-hetero couples go into nonmonogamous situations, like swinging, and the man sees his "possession"---his wife/partner---being worked over (and WELL) by another man, that man's ego shatters faster than a glass window penetrated by a brick; in the case of the "Classic Prudie" husband and many men like him, his life is never the same, he becomes more and more insecure about his own sexual prowess as a man, but instead of understanding that this is an internal failure of his own making, he projects his toxic insecurities about his manhood onto his partner/wife, leading to resentment and, due to his adhering to patriarchal ideology about manhood, he will never disclose his feelings to his wife/partner unless he becomes angry enough, and then weaponizes the entire thing against her to shame her...for going along with what was HIS IDEA in the first place!
Or, in the case of open relationships, the married men who suggested opening up the relationship often find themselves not going on as many dates as they hoped, meanwhile, the married women often end up having the time of their lives. I can only guess that through opening up the relationship, the married women are able to get more in touch with their own sexuality, realizing that it is not something to be hidden as if it is wrong or bad, and caring more about experiencing sexual pleasure, destigmatizing it, maybe even having epiphanies about their primary relationships and the patriarchal ideology that stumps its growth. Meanwhile, the married men are so caught up in themselves and the lack of sexual access to other women, become jealous of their wives, kicking themselves for suggesting opening up the relationship as if that was supposed to fix something that was lacking within the marriage and would be easy to navigate.
The only thing that comes easy in ethical nonmonogamy is that it easily exposes cracks within primary monogamous pair-bonding; nonmonogamous relationships require the same amount of honest and open communication and solid foundation of trust, love, and healthy boundaries that monogamous relationships require, and the fact of the matter is, folks who jump into nonmonogamy thinking it's easy know nothing about it, nor are their primary relationships strong and solid enough to deal with the challenges that come with nonmonogamy. And when those challenges present themselves, it not only makes the foray into nonmonogamy turn unethical, it more than likely brings down the primary relationship.
Before even fathoming jumping into ethical nonmonogamy, your primary relationship must be solid. Talk about the reasons for thinking about opening up/changing the relationship boundaries, air out all grievances, and understand that this is not a sole journey and it is not just about YOUR physical wants. Most importantly, divest yourselves from patriarchal ideology and its antiquated (and TOXIC) definitions of manhood, womanhood, sex, and sexuality.
Because until you do, when it comes to ethical nonmonogamy, you'll be like nothing more than a child who continues to scald their hand on the hot stove.