for as long as one can remember
Fixed expression used to describe something that has been true since one's earliest memories.
He has lived in this town for as long as he can remember.
I have never been abroad for as long as I can remember.
A set phrase combining 物心 (awareness, understanding of things) + ついて (from 付く, here meaning 'to become attached/aware') + 以来 (since). The exact historical derivation is uncertain, but the expression is conventionally used to mean 'since one became aware of the world'.