I think I understanding the ending now.
So.. after Dhristi go back to her own time. She met Karan who is obviously Karna in the mahabharata time. This cause her curse to be lifted? Will they be together? Maybe u never say for sure. Either way a good ending for DhrstixKarn fans.
At the same time, you also gave a satisfying ending to DhrstixArjun fans by making sure they never forget each other even ending the story with the last lines being those two saying good night to each other.
Or am I wrong?