You simplified it too much. Param and Hwi had a closer relationship that was more then just physical but it wasn't official and then Mr. Han came in so inconveniently when Param was steadily moving on. Which made Param have conflicted emotions since he wasn't over him and then Mr. Han peeped that Hwi and Param relationship was very close and Weaseled his way in between, took advantage of Param unstable emotional state and slept with him thus would cause a rift in their relationship and get closer to Param, to have him rely on him in a weaken mental state.
Luckily Param ran away this time from his advance but this was clearly sealing up a heartache and he wouldn't go down quietly but instead sneakily manipulated the situation to his favor. So we have 3 options, 4 maybe...
1:Unpredictable, while Param is figuring out his feelings between the two we could have a plot twist where the shadow person Param was feeling guilty about comes around and complicate things more or some other variables.
2:Mr. Han, Param gives in and seeks refuge with Mr. Han, distancing himself from Hwi
3:Hwi, Param goes to Hwi or Hwi goes to Param or they could just meet while looking for each other and they heal their relationship and overcome the obstacle of Mr. Han
4:Struggle, the story progresses and it could just be a threesome and they continue playing tug of war with Param and Param have difficulty choosing
But in any case it wasn't getting even because Mr. Han moved after the he already knew Param was with someone else and didn't take the chances he had when it wasn't too late and bacame a shackle that prevented Hwi and Params' relationship from developing.
Param having sex with Hei was fine, Param having sex with Mr. Han was not fine
Main point fuck Mr. Han, I was disappointed, disgusted and ashamed at the the sex scene between them but Hei and Param is the ship for me.

param and hwi still fucked even tho mr han said he liked param so for it to go the other way really makes no difference, if anything they're just even at this point so idk why feel bad for hwi when it happens to him now anyways param is still a whore lmaoo