I think a throuple ending (Mallory/Amanda) might be possible, but I don't get the feeling that either Jaye or Mallory is willing for the open relationship to be a permanent aspect of their relationship with the MC (he will eventually have to choose either Jaye or Mallory and won't get both.
I'm curious if this will be forced in the next update or if it will be decided in the final chapter.
I am hoping for epilogue moments with my choice (I happen to be a Jaye first guy) and I can see Mallory remaining a dear family friend, given everything that she, Jaye and the MC have shared.
We'll just have to wait and see what the devs have in store for us.
Cheers!!