MC and ML are dating since the start. MC supposedly hates Shen Bailou (ML's so called brother) because he made ML (Li Quyim) suffer (it's explained in the first or second chapter). Because of this, ML is always pretending to be another person when actually he (okay this is the confusing part), essentially Li Quyin and Shen Bailou are the same person. Shen Bailou is a stage name, Li Quyin is his real name. Because ML knows MC hates Shen Bailou, he pretends to be a person he isn't to differentiate between Shen Bailou and Li Quyin. To summarize the pretending part, when Li Quyin is with MC he pretends to be Li Quyin, who is know for being sweet and kind while Shen Bailou is known for being a shitty bastard. In actual reality, Li Quyin's real personality is more towards Shen Bailou. It's actually ALL a misunderstanding and is mainly what the book builds upon.

They met at a bar where ML seem to have developed an interest for MC. After realizing he (ML) can talk so much and still be spirited and happy, he pretty much claimed love at first sight. MC, who was interested in the concept of dating accepted to date, and as he got know ML, fell for him.

As MC watched movies by ML, he keeps having the feeling these 'gentle' role persona resembles a lot like LQY, dude he fell for. Gentle role played = his boyfriend = (... get it?) Not to mention ML is a recognized actor and did lie about his identity ("fake" name, fake family member, fake job...) (with pretty good reasons though)

ML's agent! MC assumed ML was aware of his agent's action! Ex: his car got wrecked, forceful "invitations" despite rejection, etc. Please, you can say he shouldn't assume, but when an employee does a mistake, most ppl's reaction is to look for the boss!