I'm so sick of "marriage makes you live longer" being treated as a cutesy factoid. How about "we live in a deeply alienating society that can make you so lonely you literally die, and then we tack most of the responsibility for fulfilling people's social support needs onto one very specific high-stakes social arrangement".
In couples where it's a man and a woman, the woman's longevity isn't vastly different from that of a single or divorced woman.
I think some of the studies also make the point that women are socialised to form other friendships, etc, but men often not so much, and that's probably a factor.
Also those men that live longer are almost always basically parasites sucking the potential extra longevity out of some poor woman