So like many others I followed Wookieepuppy's solution and only unlocked the achievement for writing the next chapter. I would like to thank them for a great solution I just went a step further.
So I thought about the only time that I got the icon that my decision would pull the twins apart: in the Plushie Battle scene I showed interest in Michael.
So continuing from there I did the following decisions:
In Chapter 2
Chose Tyler's goodbye scene by the totem pole in the graveyard.
Rejected Tessa at Mary Ann's grave.
While on the bench I chose selfish/accusatory dialogue for Tyler.
At the dock I pushed Tyler's resentment and had him try to guilt Alyson into helping him.
During chapter 3:
I did not tell Michael about the twin's powers.
Failed the breathing exercise outside the police station.
Did not tell Chief Brown the truth.
Yelled at Sam and confronted about his drinking and in general was hostile to him.
Did not fish for the 2nd and 3rd fish while choosing the negative, Tyler suffered more than Alyson options and rejected his interest this time.
Skipped all puzzles in the loft, kept trying letters (then back out a few times) until a crowbar was mentioned, got it downstairs on the floor by the hole and broke the box. (Thank you Kryostega for the extra details)
Finally, I chose the memory that Mary Ann was trying to kill young Tyler.
As a final move I cut the call to Tyler as short as possible by pressing B.
Remember to use the Y button to skip cinematics, but be aware that many of your important negative decisions require the X button. So you still need to watch what you are doing.
This took me an hour to speed through.
Please let me know if you need anymore clarification. Like I said I had gotten all twin bonding icons before the plushie battle. It might take less bad decisions than what I did but I did not want to have to replay this game a third time so I went back to half way through Chapter 2.