According to Peterson, enforced monogamy (i) refers to a (non-binding) social norm in favour of monogamy, and (ii) is a term used to mean this in anthropology. In order to address this, let's consider Google Scholar results.

First, how large is the literature on monogamy? If we search just monogamy, it gets me 79,300 results as of today on Google Scholar. That's nothing to sneeze at, and gives us a benchmark to compare later results to.

So what happens if I search "enforced monogamy"? There are 630 results. Again, that's not nothing, although it is obviously not a very common topic (to compare, 'geometric morphometrics sexual shape dimorphism size' gets 10,500 results, and that's just about differences in the size and shape of males and females of a species using a somewhat common method).

But what do those papers mean by enforced monogamy? The first is not an anthropology paper, in fact it is about a controlled breeding where the experimenters forced them to mate monogamously, and its effects on the results of those experiments (e.g. greater levels of inbreeding depression, etc). The second is again not an anthropology paper, it is another evolutionary paper this time on cockroaches. These cockroaches have various biological mechanisms in order to ensure that during the female's first reproductive cycle, they are unable to breed with other males after their first male.

Let's fast forward, what does the first page look like overall? Mites, fruit flies, beetles, more beetles, cockroaches, and so on. Nothing mentioning human beings on the entire first page of results. I'm assuming that anthropologists don't tend to run fruit fly labs but I might be wrong.

Now let's try another filter, what if we search '"enforced monogamy" anthropology'? We now get 200 results, when you account for the fact that we don't expect the majority of these results to have anything of significance in them just because of accidental matches (if you don't believe me, ask anybody (including myself) who has performed a systematic review, out of those 10,500 papers on geometric morphometrics and sexual shape/size dimorphism, about 185 actually record sexual shape and size dimorphism using appropriate geometric morphometric methods), this is not that large of a literature for any topic.

But let's try to make that more clear, if I look at the first result, what is it? It is a paper on Drosophila melanogaster, our old friend fruit flies, the second is an anthropology review that cites the aforementioned fruit fly paper but only uses the word enforced monogamy in citing the title of the fruit fly paper, the third tests the fitness effects of remarriage in a society where remarriage was illegal unless their original partner died. In other words, it is about legally enforced monogamy, not a "social norm". The fourth article is about insects again, the fifth is a behavioural ecology paper that uses the term in an off-hand example of a possible research question, the sixth is from an economics journal (read: not anthropology), the seventh mentions it when talking about the captivity of women in special facilities where their husbands visited only for sex in certain historical societies (sounds like a bit more than a social norm!), it is part of a book on the evolution and history of rape, the eighth is about the disastrous consequences of enforced monogamy in the form of marriage laws (sounds a bit like... legally-enforced monogamy?), the ninth is a review of a biography of an anthropologist that mentions enforced monogamy without defining it only to say how the anthropologist became aware of its catastrophic effects, and the final one on the front page is about a political philosopher (Hayek).

Does it better if we go further through? If we go to the last page of results, we get a collection of essays on 'musicology', a biography of a lecherous philanthropist, english literature papers, etc. No anthropology papers using it the way Peterson does in sight.

It almost seems like it isn't an anthropology term? And that when anthropologists do use it off-hand, they use it to refer to legal enforcement of monogamy (e.g. outlawing remarriage).

Wow, it is almost like Peterson is making things up to appeal to incels and then trying to hide it under an academic veneer.