Cunning Single Lady (2014)

It is not exactly the same...actually quite different but still gives similar vibes.
Both are second chance romance.
Both leads work in the same office.
Love triangle
Male leads later realize how female leads also had to make so many sacrifices and recognize their faults as well.
Happy Ending

My favorite thing about both shows is not simply the Candy FL, but rather the slow realization from the ML that all of his thoughts about the FL are biased and wrong.
If you loved all the scenes with Lee Seung Gi feeling guilty, then try this one too.

In the same vein, I also recommend Thirty But Seventeen and I second someone else's recommendation for Stars Falling from the Sky