The 3-Year Glitch is the New 7-Year Itch
It used to be that couples lose romantic interest in each other after seven years of marriage. Thanks to modern life, however, the "seven-year itch" has been upgraded to the "...
https://www.neatorama.com/2011/03/10/the-3-year-glitch-is-the-new-7-year-itch/