Are you actually confused by this concept?
One large barrier to breakup is how much damage a breakup will do and how much effort it entails.
If a break up is very easy then small insults will lead to break up.
A marriage contract is.. a legal contract; thereby it can be a barrier to a break up.
I have considered breaking up with my girlfriend before yet the effort of splitting our things and ensuring that she has a nice continuation of a place to live comfortably has caused me to reevaluate if the reasons I want to break up are good enough. That's all the parent was suggesting. Does the marriage contract have any bearing on keeping people together.
That’s probably why that’s all they’re looking at. It’s the only thing that can be measured as a proxy for stable relationships.
Not the ridiculous idea of people who thought they were married but were apparently not due to some technicality or bureaucratic error which they were not aware of.
BTW, shouldn’t “widower” be the person who died and the survivor be called “widowee”?
“Etymology Middle English widewer, alteration of wedow widow, widower, from Old English wuduwa widower; akin to Old English wuduwe widow”
It's one of these more universal words of Indo-European origin: https://ids.clld.org/parameters/2-770#2/14.4/149.7
this is where we try to control for the positive material externalities that come from sharing resources among people. you dont have to buy two of everything if you share, it's cheaper to add a room than obtain a whole house and duplicate bathrooms + kitchens etc.
widows would fall afoul of this (in the sense that they've lived with that advantage for most of their lives), as well as obtain a likely wealth effect from inheritance, but it wouldn't surprise me if the entirity or majority of the marriage effect is largely just a restatement of equivalisation + social transfers/safety nets.
I was a child of divorce, and honestly it was a bit traumatizing. My parents were (and still are) often quite angry, mean and dishonest. They spent literally over $100,000 on legal fees, but "didn't have the money" to buy me a guitar.
So despite being (relatively) well off, coming from a violent, if not outright abusive at times household, suffering from parental neglect... yeah honestly that may have contributed to things like "skipping class to do drugs".
I think there's a lot of socializing that can happen in a functional two parent household that doesn't happen in single parent households, and this may be an additional advantage, in addition to equivalisation + social transfers/safety nets.
Plus as previous comments have said, if your parent has the trait "functional, responsible adult capable of having healthy relationships", that probably really increases your outcomes.