Many are no longer. Fortunately in the US we're free to live the arrangement that works best for each pairing, or group.

Cultural norms take generations to change and we are right in the middle of some of them. Swinging only became a little less taboo in the 60s. Polyamory was barely heard of 30-40 years ago and now more people are open about it. B&D themed commercials are all over TV and the radio. The Folsom Street Fair in SF and Love Parade in Germany would not have happened 5o years ago but are very common now.

Although Folsom has to be a bit of a shock to the folks from Iowa with their kids who stumbled onto the festivities.

Because genital herpes among hundreds of other potentially fatal diseases, not to mention huge quantities of drama, are not appealing?

I have never seen monogamy as a religious issue, but here is an article which evaluates the potential roots of monogamy.

[healthland.time.com]

Since statistics show that it's mainly men who resists monogamy, overtly or covertly, I also wonder what men who covertly practice polygamy would say if their spouse decided to take a female lover. Bet i could guess it would be outrage, or it could be a request to participate. LLOL

Up to my 30s i refused to make the commitment to any monogamous relationship, openly and without scamming anyone. Hurting anyone has always been my worst nightmare and betrayal always hurts another.

Since my 30s, i have been a serial monogamist, mainly because i had decided that when i gave my word to anything, respect for myself and the other required that i keep it. Most women i met wanted an explicit commitment to monogamy. If the relationship wasn't working, and i couldn't fix it to our mutual satisfaction, i moved on, grieved, then eventually became open to another relationship.

Besides which, one mutually satisfying relationship can be complex enough without the juggling polygamy requires. LLOL

Beats me. Religion has one hell of a nerve regulating sex which is so wonderful. No one should tell you that you have to be married to enjoy sex. These evil people got in control a long time ago. I say we throw them all out and do as we like.

I wonder how you'd explain monogamous birds. ?

This whole "spreading the seed" thing doesn't wash well in the big picture with dwindling resources, the cost of effectively raising a child these days and over population.
Seems to me those who can stick around to ensure the family's well being, the progeny, rather than dividing those resources across thinly, is where it's at now, despite this trend to make poly seem like the end all be all.

And since this may well be a genetic predisposition that will one day have a marker the hue and cry promoting this "seed spreading" premise begs the question. What's in it for the progeny, let alone the mother, in these particularly cut-throat days, to have this type of "sire"? Not much.

Finally, if you(global) bleep up enough for long enough may have the pleasure of the cost therein, spending days deteriorating alone, with no one to care enough to wipe your posterior in the end but some anonymous health care worker, while those left in your wake are off fending for their own survival, in an overpopulated, resource strained world.

Because religion isn’t about institutions and dogma, it’s about how we live our lives. It’s baked in to Homo sapiens, even those who deny it. Religions don’t make morality - morality makes religions. Or not. In any case, morality makes behavior, and we can call the behavior religion, or we can not.

I've never been religious and I'm monogamous. And, I'm perfectly happy that way -- even as an atheist, aren't I?

I like to think that the enlightened future will be everyone freely choosing what works best for them and receiving support from society for their choice.I'm polyamorous, but I don't think it's inherently better. Believing poly or mono relationships can be healthy choices made by caring individuals is better.

Your question made me wonder about marriage ceremonies in LDS groups...do you suppose Jeffers' cult has any reference to "keep thyself only unto her" as WELL as "keep thyself only unto him?"

Other than that...monogamy does protect children. I've seen so many children hurt by a divorce because one parent couldn't keep their lust under control.

Out of no sense of personal planning, or religious, or any kind of conscious philosophical choice or intent, I became what has been called a serial polygamist; i.e., I've been married and divorced 3 times sequentially. The idea of monogamy is not universally a religious one, there are and have been numerous religions wherein polygamy is, or has been tolerated, even encouraged. In the USA, monogamy has become codified, thereby delegitimizing polygamy.

Marriage is where the religious aspect really weighs in as it was, in large part, and primarily, encouraged by the church to give men dominion over women and whatever property they may have, whereupon ultimately, the church would benefit by being the architect of that arrangement.

I can almost guarantee in only 10 thousand yrs. Of monogamy and polygamy we r no longer promsicuous habitually your just brain washed into believing and if that works for u good for u I don't imagine u would see it the same if not.

My preference for a monogamous relationship has nothing to do with religion and everything to do with my desire to have an uncomplicated life. Polyamory would cause far more stress than satisfaction for me. Also, I feel I am deserving of a man's undivided attention. I shouldn't have to share if I don't want to share.

Some people are hardwired monogamous, some aren't.
Some are culturally encouraged to monogamy, some arent.
Religion has its impact but those chains are being shed more every year.