I know you are going to find this hard to believe, but the opening sentence of this Daily Mail article is deceptive:
Being married can make people more prone to depression, a study reveals.
In fact, being married does not make people more depressed. The study shows that when a marriage is filled with nagging and conflict, the spouses are more likely to be depressed. Also, when people are depressed and stressed out they are less likely to be about to respond to positive experiences:
Constant nagging and domestic spats are significant triggers of long-term stress that cannot be outweighed by the positive aspects of wedlock, scientists found.
It can also make husbands and wives far less responsive to positive experiences.
In a successful marriage both spouses work to cultivate domestic harmony. They know what their roles are and they fulfill their duties. If they believe that each household task should be the occasion for a nagathon, a struggle over who does or does not do what, the strategy will breed depression.
I will leave it to you to figure out why so many marriages have become nagathons.
Of course, when it happens, many spouses decide that the best cure for a marriage-based depression is divorce.
Sad, but true.