Haesoo shouldn't be with either of them. It doesn't make sense being with some as toxic as Joowon and it doesn't make sense forcing yourself to be with someone, like he is with Taekyung.
Haesoo needs the time to be in his on and figure out what's best for him as well as his mental and emotional states. Nothing positive will come out of dating either of them.
It is self destructive.
I love this song...