
So does Momo love Suda or not?

Right! That question wasn't answered, huh? But my guess is he didn't, he was waiting for Suda to show gentle affection, what Momo has been wanting for so long, then he'd actually fall in love with him but since Suda didn't, Momo never fell in love. Yata did, so Momo finally let go and let himself fall for him.

Whats going on in here? Im confused (/TДT)/

From what I gathered - basically they are trying not to step on each other's toes.
Each one feels like the other has this amazing life they are working hard for and they don't want to ruin it.
Honda is afraid his boring/average life will ruin Kaido's dream. OR that he will do what he did in high school and start rumors. Again ruining his dream
Kaido is scared for the TV crew to follow him around for a week because that would expose their relationship. He seems afraid it will hurt Honda and get in the way of his club activities, job hunting, and schoolwork.

So Mookyul actually in love with his Dad? Because he seems so pissed when he ask Sangchul about his position in his Dad eyes whether he's a lover or what and he always seems so lonely and bad mood when his Dad couldn't get in touch with him ╥﹏╥ Im having an heartache here ┗( T﹏T )┛

How to put it : the chairman took an abandoned, lone and freezing Mookyul off the streets, fed him, raised him and so on, plus, because of his sick mindset, started this sexual relationship since Mookyul's early teenage years, fucking up his notion of what a family is, all the while making him feel like he was only a dog...
So yes, Mookyul definitely felt something akin to adoration. Mix that emotion with the feeling of being the chairman's only family - the closest person alive - but at the same time resentment, loneliness, and being completely aware of the impossibility of any improvement of this relationship. Moreover he shows signs of borderline personality disorder (in the main story). It's just tragic.
Mookyul had been mind-controlled and trained to absolute loyalty.
So I guess there are many kinds of love, this is an unhealthy example.

Why Keiichi let that guy kiss him? Is it consider as he cheat on Shingo? What Keiichi feel inside when he said he's not feel anger or sadness? Is it because he feel tired of Shingo unsecurity behavior? Please somebody explain it to me (/TДT)/

I think Keiichi let that other guy kiss him because he wouldn't think anything about it (I still consider it cheating). And when Shingo tried to kiss him, he avoided it because he had kissed that other guy. I think he didn't want it to mix. But that made Shingo even more insecure.
I'm not really sure what he really felt but I think it's something like guilt or something like that. Because he keeps saying he didn't want to say something so hateful that will make Shingo sad but he still did.
I don't think he was tired of Shingo's insecure behavior when they broke up. Instead I think he found out about how Shingo felt when they reunited at last. I think he was just disappointed that Shingo could no longer feel or smell his scent.
I hope this worked (=・ω・=)
Adding BDSM tag ლ(´ڡ`ლ)