Exactly. Why would two people want to spend their lives together is they make each other unhappy? Good point. Well love, here are my reasons
1.
SOMETIMES (when they’re not too terribly busy being unhappy) they make each other REALLY happy, like I could die today and I’d be okay with it happy
2.
Out of all the people in the world, those two make each other the least miserable out of all the other options
3.
They enjoy being frustrated and angry and on the verge of tears all the time
4.
Like all other humans, they’re destined to disagree, and they fully accept the reality of unhappy moments as long as there are other emotions shared between them as well (like I don’t know; say love)
5.
They have no choice (arranged marriage, hostage situation, etc.)
6.
The survival of the human race depends on it (nuclear bomb explosion/zombie apocolypse; they are the only two members of mankind left)
7.
They’re too stupid to know better (self explanitory)