@Park Byul
There's something wrong with this entire comment though.
1. MC and ML aren't together. So basically he isn't ruining anything. He just wanted to take his shot on things. He's not breaking into someone else's relationship.
2. It's not a red flag. In the end, the MC had the power of choice.
Antagonist is quite far from Dohyun's character. Just because he's the rival love interest, doesn't automatically make him an antagonist.
"If you want to be in the rain, I'll accompany you."