I recently read this blog post by Wesley Fenza. I agree substantially with two of his points. While monogamy is a valid relationship style, I think monogamous culture has some pretty awful norms that polyamorous people have been shy about criticizing for fear of coming off as nonjudgmental. And I agree that collectively, as a culture, we all need to calm down about STIs. However, I disagree with his middle point about not enabling cheaters.

I don’t think it’s obligatory to investigate thoroughly whether someone is cheating on a monogamous partner before you hook up with them casually. If someone at a party who is wearing a wedding ring is flirting with me, I will naturally assume that they are polyamorous and that their spouse is okay with it; I do not think I am required to go find their spouse and check that the spouse is okay with it before I flirt back. And there are some limited circumstances in which I think cheating is– not ideal, but the best way to deal with an awful situation. Obviously, it is not unethical to help someone cheat in cases where it’s not unethical to cheat.

I also think that commercial sex has different ethics from non-commercial sex. Frankly, if all sex workers adopted an attitude of “I won’t help people cheat”, then most of them would have to get second jobs shortly afterward. In the vast majority of cases, it is not the job of a person selling a service to check whether the service is being used ethically. Just as the restaurant owner does not inquire about whether I’m spending money in his restaurant that I should be saving for my children’s college education, the GameStop manager does not inquire about whether I am planning to give Chainsaw Death Mayhem III to my two-year-old, and the Home Depot employee does not inquire about whether I’m planning on using the Drano to poison my mother, the sex worker does not inquire whether I’m married and, if so, whether I have a justifiable reason for cheating.

Caveats aside: Fenza argues that the harm is in the proposition of infidelity; once infidelity has been proposed, there is no harm in committing it. This does not seem to be true to me. I am not monogamous, but my partners have made other promises to me. For instance, my fiance Topher has promised that he will not lie to me, even little white lies. It seems clear to me that, while Topher planning to lie to me is a violation of that promise, him actually lying to me is an even bigger violation– just as a lie that lasts ten minutes is less of a violation than a lie that lasts ten years. And while the violation is fairly severe if he intended to lie to me and was stopped by external circumstances– perhaps I already knew the truth before he could lie to me– it’s even worse if he actually does.

Partially, this is because many monogamous people are monogamous for reasons other than valuing their partner not desiring to have sex with other people. Many monogamous people are extremely averse to STIs or afraid that their partner will have a child with someone other than them. Other monogamous people fear their partner enjoying sex with someone else more than sex with them. Others do not want their partner to expend their emotional and romantic energy on another person. Still others feel a gut-level, arational revulsion at the idea of their partner having sex with someone else– a revulsion that cannot be explained or justified. (Of course, many monogamous people have more than one of those reasons, or a reason not listed, or have not introspected enough to know why it is valuable to them.) For all those people, actually having extra-relationship sex is a harm above and beyond the harm of taking steps to have extra-relationship sex.

I disagree as well with Fenza’s idea that we do not hold people responsible for enabling others to break promises. My friends do, in fact, hold me to my commitments. For instance, they have a commendable habit of frowning at me when I am tempted by egg-filled baked goods. Naturally, some of my friends don’t support animal rights, so they’re unlikely to take it much farther than a frown (by extension, there is no reason for someone who holds that it is perfectly fine to lie to your partners and break your promises to not aid in cheating– but this is an uncommon enough moral belief that I will skip over it). And I do think it would be a bit much for even my vegan friends to absolutely forbid me to eat egg-filled baked goods; they don’t get that much say in my life.

But if a vegan friend is treating me to dinner and I am dithering over whether I will order the deliciously egg-filled brownie, I think they’re well within their rights to say “I’m not paying for that.” They are causally involved in the obtaining-a-brownie process, and they have a right to prevent a thing they consider immoral from occurring. It’s not completely preventing the thing from occurring either way– I can pay for my own brownie, and the cheater can find someone more amenable– but people have a right not to involve themselves in situations they deem harmful.

Of course, one of the most important reasons not to help someone cheat is not that it’s unethical– just that it’s unwise. Fenza does agree with me here, but I’m talking about it anyway because it’ll be brought up in the comment section otherwise. Under most circumstances, a person who cheats on their partner shows that they are of poor character in a way that directly impacts such key relationship skills as “not lying”, “doing what you say you are going to do”, and “caring about whether you hurt your partner”. Cheating also means you will probably have to hide your relationship and that the cheated-upon spouse will probably be extremely angry at you.