ok this might be a bit ranty and may need to add stuff
Well, it seems that the most useful benefit for being in a dual partnership is that there is a high chance the marriage will be both long-lasting (and happy). Duals seems to stay together, as well as being compatible for each other. Other pairs seem more likely to split, or get bored of each other. It seems like other pairs may stay together by working on things or split because they decide it's not worth staying together. If you split from a long-term partner, say in your 40s/50s, this is likely to be costly and you may lose out financially- you may end up single for a while, living alone which is more expensive.
Duals (also maybe super-ego too) tend to stay together, even though many probably do have problems after many years together. They keep the relationship going and live comfortably. But they are not necessarily happier than a non dual-couple who split and go on to find happiness in a second marriage/ partnership. Yes, it's a nice idea to be with one person always and focus on your family/life you shared together (seeing your grandkids grow up together, seeing each other grow and change) BUT it's not the only type of happiness.
So there is more of a risk by not being in a dual couple. The couple might split up and never find someone else. But it could also be seen as an opportunity- a chance to relive your youth(?), a chance to experience new love again..or even a chance to find a dual haha.
I do think, on the other hand, there are a lot of couples who stay together who aren't compatible. They might not feel able to split up due to financial reasons or they have become too emotionally dependent on each other. (Perhaps his happens more in ‘bad’ ITR). So in that way, duality is the most ideal relation, it has less chance than other ITR of keeping people together who shouldn’t be.
However, with some of those couples there truly is a bond that keeps them loving each other and helping each other where they can. My own parents would be an example of this. My parents are a supervision pair and had several children together. If they had decided to separate, I really think my father would have struggled to meet someone again (he is a good person, but in a very quiet way). I think there is a bond where my mother feels needed and she's happy with that. She is also happy that she had loads of kids (ESE).
I do agree @Sol that duality is great in the way that the couple can be so helpful to each other. It is probably healthy for a society to have many dual couples, as perhaps this makes them more likely to be happy people, who can in turn be useful and helpful to others. But non-dual couples who find some sort of happiness together probably fall into a sort of faux-dual like existence. They help each other where they can, they find a way.
Also, I just find the word ‘duality’ annoying. Not really sure why lol. I guess it sort of hints at this zen peacefulness that can be achieved in oneself, but for most people in the world, they’d be very lucky if they lived a life on that level of happiness. MAYBE I’ll GET THERE YET. Lol. Actually, that’s how I see SEIs, just zen all the time.
Also, as much as I love this forum and the kind souls on it, and really sympathise with those who have struggled in life (as have I), sometimes it does all seem a bit ‘aspirational’. It’s all about being finding healthy love and meeting the ‘one’ and settling down. Where is the romance? Young people, it’s ok to be with someone in your early twenties/teens that isn’t the person you’ll end up married to..
I don't think I've really explained the bourgeois bit but I got impatient to post. I guess, essentially, duality is sold as this idea of perfection, perfect health and happiness, reaching a rich, zen existence..and really the fastest way to finding that type of happiness is not through finding a dual. It's through enjoying your life and finding support from a number of sources. Yes, healthy relationships are important but they don't have to come in the form of a dual. I think the descriptions of duality are almost a description of happiness and you can find that with a non-dual or through happy life experiences. It almost does an injustice to those couples who are non-duals and the love they have for each other. There should be more positive descriptions on non dual-relations in my opinion..
Also....love is love. I have a close friend in a happy relationship with their look-a-like partner. I know another in an activity pair. I think they’d be horrified if I told them they were better off with someone else? I think when you’re in love, and it’s going well, you achieve a type of duality. I don’t think you really notice the negative aspects of the ITR as much as you do, say with a friend or a stranger. I also know a happy mirror couple, together 15 years..
Would the world benefit from knowing about duality? Maybe. But the world would also benefit from simply knowing about ITR and using socionics to help them understand and appreciate people. Not everyone can hang around for a dual, but socionics more importantly can help people feel better about who they are..and help them achieve success in life. The more people who are enlightened about psychology, the more equal the world is likely to become, the more people will be caring towards each other and enjoy their time on this earth.