I think your understanding of evo psych has some serious holes in it.

You don't need true universals. A preponderance is pretty good. There will be variability. The existence of people who kill themselves doesn't undercut the reasonable idea that we have an innate tendency to want to stay alive. The existence of gay men and men exclusively attracted to prepubescents doesn't undermine the idea the evo psych idea that men have a strong predisposition to want sex with women. There is variability.

I wasn't arguing for monogamy being innate, I was arguing for women being upset about sex under false pretenses. In fact, there is some evidence that women who have lined up low-status men to help them raise children may secretly seek high status men (with better genes) to actually father those children.

I don't see how your latter points bear on women and monogamy. In fact, the standard explanation I've heard for concealed ovulation in women is as a support for men staying around to care for existing children, since they can't just show up during a brief period for fertilization to beget the next one.

Adult women of course decide to take the risk on "false pretenses", but they are better able to detect false pretenses, and better able to handle their distress if they fail. There is a very small countervailing up side, as girls below their mid-teens lose very little if adults are prohibited from having sex with them for a few years. Of course a great deal of any harm that happens from young teens engaging in sex is due to a whole constellation of social factors. I'm just suggesting that the innate aversion to sex under false pretenses will be a force pulling against such a major societal change that dictated that such activity was just fine. For comparison, the kibbutzim did make children's houses work for a while, but parents' innate tendency to want their kids sleeping near them won out.

The bigger factor is that I don't think society is going to change dramatically in those respects, and I don't want it to (though I would like to see many changes liberalizing attitudes on sexuality).