为她掏心掏肺对我没心没肺
[wéi tā tāo xīn tāo fèi duì wŏ méi xīn méi fèi]
Suggesting the user sacrifices wholeheartedly (metaphorically emptying out their internal organs - heart and lung) to help another person while that person shows absolutely no concern about them. This portrays lopsided dedication in friendship or romance relationships where effort and response aren't mutual.