我也羡慕曾经有个你的自己
[wŏ yĕ xiàn mù céng jīng yŏu gè nĭ de zì jĭ]
Translates to something like 'I also envy myself who once had you'. It carries feelings of nostalgia and envy toward an older version of oneself when a specific person was still present in their life.