Both dramas have three couples. The females are friends who fall in love. Each drama has an older female/ younger male couple.
They are both rom-com dramas.

Differences: occupation of individuals, how couples get together

Both dramas have three couples, who have equal amount of time on screen.
The females are all friends who fall in love.
They are good rom-coms.

Also one couple in both is an older female/younger male.

They both involve time travel. While JFL is only for a moment back in time and TPR they travel back 20 years. Both involve the couple traveling back together. Both show a couple that had misgivings and who did not get along but later on they create a strong bond.

Both involve schemes in the court that can only be stopped because of the time travel to give the couple the edge.