爱情是大姨妈疼完就走
[ài qíng shì dà yí mā téng wán jiù zŏu]
'爱情是大姨妈疼完就走' is a humorous analogy comparing relationships (romance) with menstrual pain. The underlying meaning here could imply romantic relationship ends just as quickly once menstruation pain disappears, reflecting on short-lived passionate affairs.