지 오래됐어

it's been a long time since

→ 지
phrase Rare #16,586
it's been a long time since Follows a verb to say that a long time has passed since the action. The ending 됐어 is informal.
KO: 한국에 온 지 오래됐어.
EN: It's been a long time since I came to Korea.

우린 오린을 본 지 오래됐어

It's been a long time since we saw Orin.

— 네버엔딩 스토리 (1984)

오스카, 할머니 치마 속에 남자 넣은 지 오래됐어

Oscar, it’s been a long time since I put a man under Grandma’s skirt.

— 양철북 (1979)