That was already included long ago mate. But to get Emma's ending, it happens after the protagonist does the horizontal dance with her, I think after that they chat about their next move and you'll reach a part where it says "Stand by your promise" and "Continue the plan" (can't recall that entirely). Select the former and that leads to her solo ending. Be advised, it's a rollercoaster of emotions, broken hearts and some dark stuff in between but it's worth it. And have some tissues ready at hand in case of possible waterworks.