I don't claim that this list is definitive, but I think it's a good start.
1) Someone has to stay home to look after the kids
Why the hell would you want strangers raising your kids? For what? Most second incomes only exist to support the persons ability to work the second income (car payments, fuel, extra taxation), or to allow indulgence in consumer whorishness that people don't think they can live without (massive home, cable TV, three iPhones, two iPads, designer goods, etc.). People who send their kids to daycare priortise status, consumer goods, and lifestyle, over their family.
Why would you want to be away from your children during the only time they will be innocent before they realise the truth about the world, or get cynical, or get their heads filled with programming of all sorts? Why would you not want to be the one who gets to instill values in your children? Why wouldn't you want to teach them while they are at their most malleable, how to live life properly?
If you don't want to do these things, why even have children? If you do want to do these things, but still send your kids to daycare when you don't *have* to, what the fuck is wrong with you?
2) Everyone in the family has the same last name
This one I'm going to argue purely from aesthetics: co-joined names are stupid and ugly. Why? Because say you get married and become Carl Brown-Cuckington, what about your kids? Do you expect your son to be Derick Goldstein-Brown-Cuckington? And Derick's kids? Our ancestors long ago realised the problem with this, hence our tradition of taking the father's last name. Keeps it simple, yo.
3) Monogamy is non-negotiable
For millennials, especially people who spend lots of time of Tumblr, polyamory and polygamy have been normalised... if not downright glamorised.
It seems these days that if you don't have a girlfriend, plus a boyfriend, plus a hook-up or two on the side, plus a transsexual orgy-buddy, a sugar-mummy/daddy, and someone you just go on coffee-dates and picnics with, then you're SO last century.
Don't you know: "it's possessive and creepy to not want your partner to sleep with or have a romantic relationship with other people?" This is the mindset of these people. They do not understand loyalty, or discipline. They are hedonists with the "if it feels good, do it" mindset that Bill Clinton epitomises.
I've thought this through, wondered if they weren't onto something with this lifestyle of theirs... But concluded: No, monogamy exists for a reason. Here are some of my reasons for it:
Firstly, between working 55 hours a week, writing articles, podcasting, working on my book, chilling out, catching up on news and researching, house work and gardening, having a social life... I barely have time to be a good partner to ONE person. I don't have any extra spare time for an hour a week worth of yoga, let alone time for another relationship! Which leads me to the question:
How do they have so much spare time? Do these people not sleep? No...
They just don't work.
Seriously though... The biggest advocates of this polyarmous lifestyle seem to be:
D) combination of the above
So for people who have lives that don't revolve around sex, OR who have jobs, monogamy makes sense purely because who the fuck has time for more than one serious, committed, loving, fulfilling relationship?
Another argument against polyamory is that we are wired to fall in love with the people we sleep with. Nature has ensured our continual reproduction and the looking after of offspring, by giving women chemicals to make them fall in love with their child and its father, and the same for men, just not as much... Oxytocin... The love drug. The brain releases it during, and especially after, sex. It makes people feel safe, loved, in love.
So despite your rhetoric about it just being casual sex, or emotionless, or whatever... You can not overcome the power of your biology with your self-indulging rationalisations. So good luck with that.
Finally, my last argument against polyamory is that people have sexually transmitted diseases, and I don't want them. Fact is: people who make sex a lifestyle, who don't care about the sexuality of the people they sleep with, or how many, are more likely to be infected. You may know who you're sleeping with, but you don't know who they're sleeping with.
4) Cheating ends it
I don't really have much of a thesis on this one, except to say that in my experience: if someone cheats, and you stay with them, things are never the same. Cheating means a lapse in loyalty, judgement, discipline, and self-control. These are things someone who is to be the Mother or Father of your children needs to have. If your partner doesn't have these qualities before you have a family, don't imagine they'll magically develop them when you do have a family. Cheating in this sense is a great litmus test. My policy is that if it is failed, it's game over.
5) Be yourself & be honest
Be your authentic, true self. If you change yourself and your behaviours to keep someone else happy, if they really care about you, they won't be happy if they know you aren't doing it for yourself.
Being dishonest is the most disrespectful thing you can do to someone, because you're denying them the opportunity to live in reality and engage with you on a level playing field. You are editing their reality for your benefit.
It is a behaviour of cowards. People who are confident in themselves and have courage will tell the truth, and happily invite people to share in reality with them, because they know that their authentic self is sufficient, and so they don't have to "edit" the reality of others to get by.
So that's my list for now. I might add more as I continue to mull this topic over. Feel free to add some others, or your own list in the comments. Cheers!