the modern serial "monogamy" is a completely different cluster of relationships from the old monogamy

Well, in the comment I was talking about in the grandparent (which I'd link to if this thing was faster) I said “relationship with my girlfriend” rather than “marriage with my wife”, which I'd think makes clear the former is what I was talking about. Maybe “monogamy” it's a bad label for it, but ‘$word is a bad label for $thing’ hardly implies ‘I'm not free to do $thing’. (And while it's unlike traditional lifelong monogamy, it's also unlike Bay-Area-technophile-style polyamory, and given that around here more people practice the latter than the former it seems more useful to me to have a word to distinguish it from the latter than from the former.)

(I'm not sure what exactly Christopher Ryan meant by “monogamy”, but he was opposing it to EEA-style sexual omnivory, which from his description sounds more like Bay-Area-technophile-style polyamory than First-World-small-town-mainstream-style serial monogamy to me.)