七年忘七年痒三秒梦三年痛
[qī nián wàng qī nián yăng sān miăo mèng sān nián tòng]
Refers to complex human emotions regarding relationships, suggesting it takes seven years to forget someone, but after seven years of being together there may be itching for a change, dreams only last a fleeting three seconds, and heartbreak from breakup lasts at least three long years, illustrating emotional turmoil over time in relationships.