Many thanks for your interest - I'm happy to hear you liked the game and are looking forward to the sequel. To answer your question, I didn't really have a canon sexual orientation in mind for the MC and, for the most part, I tried to keep it ambiguous enough for player's to decide for themselves.
Once you are on a route then the game generally assumes you like the gender of that character, but I tried to leave it up to players to decide whether the MC liked that gender exclusively or not.
I hope this answers your question and many thanks for playing