From Longman Dictionary of Contemporary Englishthat’s lifethat’s life (also such is life) spokenDISAPPOINTED used to say that something is disappointing but you have to accept it Oh well, that’s life! → life
Examples from the Corpus
that’s life• But I guess that's life!• But there you are, Mr. K. that's life.• The students shrug; that's life, they seem to say.• Oh well, that's life! 