"Show love and stop at ceremony" is an ancient description of the relationship between men and women. "Love" means that human emotions are generated between men and women; "Stop at the ceremony" is bound by etiquette.
"Show love and stop at ceremony" is advocated by Confucius. Falling in love is ok, but it can't go beyond the boundaries of etiquette. According to the description of the poem, this boundary is mainly aimed at the nobility, and women's feelings cannot be robbed or ignored. "Stop" here does not mean to stop feelings, but to stop within the scope allowed by etiquette, and you can't do anything beyond etiquette because of love.