well tbh here, falling for your childhood friend, is complicated, having your first love, first sexual relationships etc. can be too, and all that with a guy, being gay, and not having anyone to confide in either is also a factor..haha
If you think about it the seme's actions were quite manipulative, taking a lonely child, taking advantage of his loneliness and raising him to his liking
pumped up for more, looking forward to it, hoping to see more of the hot stuff ╮( ̄▽ ̄)╭