心中所念之人早已非我良人
[xīn zhōng suŏ niàn zhī rén zăo yĭ fēi wŏ liáng rén]
Translating to 'the person on my mind is no longer my beloved/good person,' it reflects a somewhat nostalgic or even sad acceptance that someone once held dear has moved on or changed such that the affection is unreturnable, lost over time due to change in either party involved.