你的过去我来不及参与你的未来我奉陪到底
[nĭ de guò qù wŏ lái bù jí cān yŭ nĭ de wèi lái wŏ fèng péi dào dĭ]
This nickname conveys a sentiment that although the user did not know/meet the other person earlier in their past, the user promises to be present with this person into the future - expressing dedication, care, and promise to stick with the other forever.