Since the mod hasn't been updated yet, I just sum up how to get the throuple ending in this chapter:
1. Reject Mallory route when she asks about relationship and enter Jaye Romance route in previous chapters, the open relationship route is false hope;
2. Make sure your love points with Mallory and Jaye are very high, i.e., maximize their love points;
3. When Jaye is feeling down, choose "Aske her what's wrong", then when in the online conference scene, choose " I'd like to phone a friend";
4. At the end of your journey with Mallory, choose "I wish things were different";
5. If everything goes well, after having sex with Jaye, she will talk about inviting Mallory back into their lives, then voila, you enter the true throuple route.