i could only bear to skim very briefly over this episode, i don't think i can handle the roller coaster of emotions right now lol.
it's very sad and heart wrenching, but this is also a very necessary step for nai and nok's marriage and relationship. everything started because of the game, even the marriage was a game, but now it's all game over, so they're getting a fresh start, no more games, no more second guesses (of them, especially nai, being unsure of the other person's feelings and intentions) - it's the real deal now.
both nai and nok have some major issues that they need to fix - on themselves and what they bring on the table to their relationship and marriage. nok needs to stop saying whatever she knows will cause maximum damage to the other person, she needs to stop being so prideful and let her husband know her true feelings and thoughts. yes, at the end he may not care like she thinks, but she has never even tried, just like how she never really truly fought hard for nai from since the beginning. like a lot of others have observed, nok is a taker, but a relationship cannot be healthy if it is always a one way street.
then as for nai, he needs to know his worth and stop belittling himself and keeping everything bottled up. also, i know he has the best intentions in mind, but he's the son in law of the family, not the fixer of everything that goes on. nai, you're only human, we all have our own flaws and emotions, and that's okay. stop trying to be perfect and mask your emotions in front of others because they'll still love you regardless. lastly, these two really need to have open communication with each other, and be honest with their own feelings about the other person, and express it alllllll out.