Someone actually created this sequel synopsis on the last episode of Ruk Long Jai on youtube. The original text was in Thai but this is the translation in English.
Jay and Pin have been married for a while. Jay is working in the provinces (which I'm guessing is the countryside of Thailand). Pin is working in Bangkok and there, she gets with another man. Ploy is working at an advertisement company. Ploy meets a really good guy and dates him, but she still hasn't forgotten about Jay. By chance, Jay and Ploy encounter each other again at a college reunion party at their university. They greet each other as old friends and end up keeping in touch. Gradually their feelings resurface, but they don't do anything to express their feelings for each other since they already have their own significant others.
Jay catches Pin cheating on him and they start quarreling. Jay moves back to Bangkok so he can be close to Pin and so they can try to sustain their marriage life. But the closer he is to Pin, the worse their problems become. Jay eventually realizes that every time there's a problem, Ploy is always there to comfort him. Ploy turns all her attention towards and uses all her effort to appease Jay. Whenever Jay is with Ploy, he feels happy and content. Ploy wants to make up for not giving Jay enough attention in the past, even if it means only being his friend in the present.
Ploy's boyfriend loves her and wants to marry her, but Jay won't allow it. Jay decides to end his marriage with Pin and breaks up with her. However, Pin's parents beg Jay to stay with her so Pin goes back to Jay.
The company Pin works at hires Ploy to work for them. Ploy and Pin have to work together and Pin uses this opportunity to reveal (or accuse) Ploy of cheating with her husband (Jay). Ploy's father becomes angry at Jay and orders him to stay away from Ploy. Ploy's father believes that if Ploy marries her boyfriend, Jason, she'll forget about Jay.
Jay has another altercation with Pin and he finally admits that he was wrong to choose Pin. Pin threatens to commit suicide if Jay leaves her. Jay is unwilling to stay with Pin because it makes him miserable.
Jay doesn't want to cause any more trouble so he tells Ploy to marry her boyfriend. Ploy tells Jay that she loves him and has never stopped loving him. She wishes that she could go back in time and admits that she was crazy to break up with him. Jay is sad for their time together lost. He says that it's impossible for them to get back together and for them to stop being hopeful in a lie (or stop living a lie). Jay tells Ploy that he'll go back to Pin and be a good husband to her, while Ploy agrees to marry Jason as Jay desires.
Jay eventually parts from Pin quietly. Pin gets involved with a client at her company and unknowingly becomes the mistress. The client's wife(?) plans to catch Pin in the act and reveals a clip of Pin in bed with a man (or her husband) in front of many people. Pin is humiliated and fired from the company. Pin goes back to Jay and pleads to get back together with him. Jay refuses to get back with Pin. Pin binge drinks and falls off a building. Jay blames himself for Pin's death and becomes very depressed. Ploy is concerned when she hears the news about Jay's condition.
Ploy takes care of Jay until he becomes mentally stable again. Jay tells Ploy that she shouldn't be interfering with him anymore because she is going to be marrying a great guy. Jay tells Ploy to go back to her fiance. They are both heartbroken.
Jay and Ploy don't contact each other for three months. Jay works hard to keep everything peaceful until Ploy's wedding day. He plans to say goodbye to his colleagues and Ploy, but he finds out that the wedding has already been cancelled by Ploy. Ploy cancelled the wedding with her groom and moved away and Jay knows that he was the cause of this because Ploy loves him. Jay tries to contact Ploy's father but Ploy's father won't tell him anything.
Jay calls Ploy relentlessly but isn't successful. Until the day of her birthday, Jay brings a handmade gift to Ploy's father and asks him to give it to Ploy since he knows where she lives. The gift is a recording of him singing "Mak Kwa Rak (More Than Love)" (just like when Ploy recorded herself singing the song and gave the CD to Jay for his birthday). In his gift is a ring also. He asks Ploy if she will marry him and to call him back if she agrees. He tells her that he's willing to wait for her forever. Ploy cries while she's reading all of this and flies back to meet Jay.
When Jay finds out that Ploy has agreed to marry him, he rushes to go meet her. Everything seems to be ending well. However, in his desperation to see Ploy, Jay gets into a fatal car accident. His car flips over. Ploy is shocked when she hears the news. She rushes to the hospital to see Jay. Jay has serious injuries and has a very low chance of surviving. Ploy realizes that Jay is holding onto her book that she made and gave to him for his birthday a long time ago, before they broke up. It's been preserved well and is still in good condition. This breaks Mo's heart.
Will Jay and Ploy's love story end in tears again? Or happiness? The sky is the only limit or take away from it. (That last sentence was a direct translation from google translate since I didn't know how to translate it into a rough translation.)
nah uuuuh, you did not just go that route and be blaming other people. You know what you did. 
If Mo didn't trust you and your relationship together then she would have never let you tested that other woman in the first place. The realization on her face when he said that to her was pretty sad, so she just said her last words and left, but he never went after her which made her cried even more because she knew that they were over 
. They both had their reasons for doing what they did and loved eachother so much at one point, but me being me, I don't agree with cheating.
