The 1970s called; they'd like their arguments back! Arguing that children with married parents fare better, thus promoting two-parent families, is akin to suggesting that since blue cars have fewer accidents, everyone should drive a blue car. Pressuring dissatisfied couples to stay together or marry benefits no one. The article fails to provide actionable recommendations on promoting marriage.
It also spells out the advantage of marriage, even unhappy marriage: kids get in less trouble, have fewer problems, and are happier with better outcomes.
Relationships are much more about your ability to handle conflict and invest time than who the other person is.