ML falls in love with 2FL during their 1 month of dating and ends up with her. While FL regrets her choice and ends up alone. This will be the perfect ending.
Only a cheater can root for another cheater. You have your answer.
So just bec I'm against cheating, that makes you think I'm against it bec I've been cheated before? If someone is against rape, will you think they're against it because they've been raped before?
Just watching a few scenes from this show, you can tell it was written by a woman for a female audience. Young women might start to think it's normal to cheat on your partner to find those "butterflies." You can just scroll through X or TikTok and see a lot of young women defending and justifying the FL's cheating.
If you can't handle someone else's opinion then don't open comments. It's a waste of your time and happiness. Let people express their opinion. You'll find comment of people who enjoy this show so just engage with them. And lastly, Mind your own business.
I checked Namuwiki and there's a change of writer. Looks like Main Cast was decided earlier and then the writer got changed. It's highly possible SML got connections with the new writer. There's no other way he's getting this much screentime and actual Male lead feels like a guest role.
K-Drama 
There goes your disclaimer.