Goong
Coffee Prince
My Girl
She Was Pretty (Korean drama starring Park Seo Joon, Hwang Jung Eum, and Choi Si Won) and the Chinese remake Pretty Li Hui Zhen (starring Dilireba, Peter Sheng, Sierra Li Xirui and Zhang Binbin)
Which Star Are You From? (He's in love with the main female lead and her older sister.. and both the main female lead and her older sis are played by the same actress, Jung Ryeo Won)
Oh My Ghostess (well.. actually, this is a trick question, since he's in love with 1 body and 2 girls...um... 3 girls at first, one of them drops out.)
And.... the classic wishy-washy guy who took the longest time to sort out his feelings about the women in his life, Zhang Wuji in any adaptation of Heaven Sword, Dragon Sabre. My favourite adaptations are the 2000/2001 TVB adaptation starring Lawrence Ng, Gigi Lai, and Charmaine Sheh and the 2002/2003 Chinese adaptation starring Alec Su, Alyssa Chia, and Gao Yuan Yuan. In fact, there's a point in the story where he has 4 love interests. Hahahaa!
There's also Romance In the Rain where Shu Huan (Leo Ku) is ... seriously always going back and forth between Yi Ping (Zhao Wei) and Ru Ping (Ruby Lin). Again, there are multiple adaptations of this but the Leo Ku, Zhao Wei, Ruby Lin, and Alec Su version is the one I recommend.