AB, you're hammering certain points you seem to be stuck on, which is your prerogative, but this is getting a little old, and the bottom line is we don't care what hard-liner monogamists are stuck on or see as inconsistent. The mainstream church culture can't figure out marriage, divorce, or adultery from the bible, so why should we care what they see as "inconsistent" in our understanding of scripture?
Bottom line: The husband doesn't "commit" adultery "against" his wife. He doesn't commit adultery divorcing his wife, and he doesn't commit adultery marrying more than one wife, so he can't "commit adultery" by divorcing his wife and marrying another. What he can do, stated most clearly in Mt 5, is "cause his wife to commit adultery" by divorcing her for any cause other than her own fooling around. He could also "put adultery on her" or "perpetrate an adultery" (some of the other ways to understand the Greek text) by divorcing her, which seems to be what Jesus had in his mind when he added that otherwise mysterious "and marries another" clause in Mt 19 and Mk 10. And that is easily relatable to the common practice in monogamous cultures (and prevalent in polygamous cultures when a man simply doesn't want to support two wives) of trading in your used wife for a newer model (aka serial polygamy or pseudo-monogamy).
Remember, as pointed out several times already in this thread, Jesus was responding to a question about divorce. Not polygamy. It wasn't about polygamy. Polygamy wasn't an issue for Jews at the time of Christ. Get over it. People who try to make it about polygamy are mistaken at best, if not duplicitous. Not our problem.
I understand your answer, but keep in mind that this is yet another type of response. It is not consistent in that it differs from the POV of some of the other respo
So a consistent, defensible position is that in Mt 5 Jesus sua sponte addressed the issue of easy divorce in a list of several things the religious police were doing wrong. Any divorce other than for fornication puts the wife in at least the metaphorical position of committing adultery. Then, when questioned later (Mt19/Mk10), instead of just repeating himself, Jesus actually went to the heart issue, the motive typically underlying divorce 'for every cause'—trading up. But the core message remains the same: Stop winking at easy divorce. Period.