In an odd way I read this as less a romance, rooting for Haru and Midori to get together (in fact, I hope they don't), so much as an emotional mystery, where both of them are trying to figure each other out. Haru knows there was some connection between Midori and her mom that she doesn't understand, but doesn't know it was one-sided love (although we really don't know what her mom felt). She's starting to figure things out, but there's still a ways to go.
On Midori's part, to some extent I don't think she realizes that she was in love with Tsugumi either. So that's part of the mystery from her point of view, processing and understanding just how she felt since she doesn't really understand her own emotions.
Plus the real need for both of them to become family and move forward in their lives of course.