live in the past

/L AY1 V IH0 N DH AH0 P AE0 S T/
verb
  1. 1

    To dwell on and ruminate about past events.

  2. 2

    To be steeped in outdated traditions, fashions, beliefs, etc.

Source: https://en.wiktionary.org/wiki/live%20in%20the%20past