他是记忆不是命
[tā shì jì yì bù shì mìng]
'He is a memory not my destiny', means the person talked about in the context belongs only to past experience or recollections, but did not or would not become part of life’s path forward. This may imply feelings towards an old love or relationship that has faded or transformed into merely a part of the past experiences instead of future expectation.