Truly I know this sorrow belongs to everyone, yet for a poor couple every matter is a grief.
Tips
history
From Yuan Zhen's 《遣悲怀》 (Tang dynasty), the second of three poems mourning his late wife Wei Cong: 诚知此恨人人有,贫贱夫妻百事哀. Yuan Zhen and Wei Cong had lived in poverty; she died before he became successful. The line's poignancy comes from his belated prosperity - the things he couldn't give her when it mattered.
usage
A bittersweet observation, not a cynical dismissal of love. Quote it to sympathize with a struggling couple, not to mock them.