I agree with this but don’t really agree with the rest of what you wrote. I think women do benefit from specific ways they are socialized, and this may be relevant to why they do better single than men do. I’ll expand more below.
I don’t see why it would need to be explained via evolution and biology. It seems like there are several straightforward cultural/socialization explanations.
Lots of explanations for this exist and are easy to find. For example, married men go to the doctor more and avoid dangerous activities more often — both commonly attributed to their wives nagging them to be heathy and safe. So that could be part of it.
The most interesting topic to me has to do with happiness and emotional support. So that’s what I’ll focus on.
I think people do better when they have robust support networks. When people care about them, support them, check up on them, hug them, listen to their problems, offer advice and assistance, etc.
These kinds of emotional support are more common in friendships between women than in friendships between men. This is noncontroversial and widely accepted outside of this sort of argument, and often a source of jokes (including jokes made by men).
For example, friendships between men are more often transactional, e.g. focused on one or more shared activities. There is a super common phenomenon where a guy says his best friend got divorced or fired or some other major life event, and the guy’s wife asks what happened and the guy has no idea. He heard about his friend’s life event and asked zero follow-up questions. This is standard for many men.
Men often say that this is just how they prefer it, that they are more stoic than women, less emotional, etc. And this is the reason why they don’t open up, share feelings, support each other, and do all that other feminine crap women do with their friends.
But men do often open up to their girlfriends and wives. They even open up to women they just met. It’s easy to find lots of examples of women wondering why guys keep trauma dumping on the first date. Or wondering why their boyfriends need to be babied so much.
So to recap, my position is that most people benefit from emotional support. Women commonly give emotional support to other women via friendship. Men don’t do that as much. So for many men, the only emotional support they get is from their wife.
Ergo, single women are still receiving emotional support (and generally getting/giving it in a reciprocal way with other women.) Single men get no emotional support, and married men get emotional support from their wives (often in a lopsided way).
I think that my individual points here are generally well known and not very controversial when looked at outside of this context. Put them all together and I think it could easily explain a large amount of the disparities in happiness outcomes between married men and women.