Every day in June, the most popular wedding month of the year, about 13,000 American couples will say “I do,” committing to a lifelong relationship that will be full of friendship, joy, and love that will carry them forward to their final days on this earth.

Except, of course, it doesn’t work out that way for most people. The majority of marriages fail, either ending in divorce and separation or devolving into bitterness and dysfunction. Of all the people who get married, only three in ten remain in healthy, happy marriages, as psychologist Ty Tashiro points out in his book The Science of Happily Ever After, which was published earlier this year.