My 2 cents on his sexuality. Perhaps a little unconventional.
In his childhood and adolescence, a lot of boys made fun of him, and some girls were nice to him. He is not good at social cues, so he learned that "boy bad, girl good" was an effective way of sorting people for their future interactions. This may also have been effected by how his parents treated him.
So now he hates all men. He discovers his sexuality by all accounts at a late age. He finds himself attracted to girls, maybe boys too. He also has been told by his parents that he should be attracted to girls. He also realizes on some level he needs taking care of. That has always been his mother's job, a woman's job. This further increases the "boy bad, girl good" reaction.
Then comes the sweetheart search. I do believe that noviophobia is really something in his mind. He legitimately wants a sweetheart to take care of him, and he sees all guys as competition. More "boy bad, girl good".
Enter the trolls. Trolls find out that he has this reaction, and take the approach of being confrontational if they are guys, and trying to be friendly if they are girls. It is a crazy upside-down period in his life, when he is living in a world almost entirely constructed by a few trolls, but he receives a lot of aggression from males, and sympathy (even if it is fake) from girls. The trolls had to use "boy bad, girl good" to communicate with him, and the end result is that they further exaggerate it.
Next comes a period of loneliness and isolation. He no longer has these sympathetic girls around him. He knows on some level that he has driven them away. Now the "boy bad, girl good" really starts to affect him. He misses interacting with girls. He believes that boys are bad, he is a boy, and may think that this has caused him problems, and may have driven away girls. It becomes unsustainable to live openly as a member of a group of people he has begun to hate. Also, like anybody, he begins to emulate the people he likes/admires. Add all of that up, and what do you get?
Tomgirl!
Thoughts?