Well he always liked touma as a friend. As for the relationship at the ending I think that’s up to our imagination cuz the manga in its core speaks about change over time. How even if one chapter of their story ends the persons life keeps going and evolving. So I imagine things happened, people grew and touma was always there for our ml so he slowly fell in love. Throughout the story we never really get masumi questions his sexuality seriously. So maybe that’s something he did in that timeskip.
Sorry I meant taichi not masumi, I was thinking of her as I was writing this
Wait I’m confused how did the black haired boy chooise idk his name start to like touma WHATT???