Chill people, it doesn't matter who this new person is. After everything that's happened, Akane is clearly head over heels for Yamada. It doesn't mean misunderstandings can't happen or that Yamada can't get jealous (he's human), but no need for second-hand insecurity here. If this much is enough to wreck what they have then it wasn't meant to be anyway. It's probably just some mild spice from this author to deepen their relationship and keep the story moving along. (ie, gomen Takaya-kun, this ship has already set sail...)