Hannah Fry quotes:

An arguing couple spiraling into negativity and teetering on the brink of divorce is actually mathematically equivalent to the beginning of a nuclear war.

The most successful relationships are ones with a really low negativity threshold. In those relationships, couples allow each other to complain, and work together to constantly repair the tiny issues between them. In such cases, couples don't bottle up their feelings, and little things don't end up being blown completely out of proportion.