I don't actually hate the MC for not being able accept things either. Maybe I just dislike the whole "a straight person forced into a gay relationship or they die" narrative. And that dislike is really showing when the MC is so aggressive at the ML when he can't control his body (you know the scenes when ML gets involuntary erection and the MC points it out, asking inappropriate questions and then calling him a pervert when he gets an answer).
Overall I see no chemistry between the two. I can see the ML genuinely liking the MC and respecting the boundaries (somewhat), but the MC seems so disgusted by everything, it's annoying the hell out of me that they are supposed to be a couple.
I'm kinda disappointed, cuz I really like the art and the plot seems interesting enough, but the characters have no chemistry.
Exactly. It doesn't help that I've actually read something similar where the plot is done better. The style is different and the relationship is very mild (as in it's a shounen ai instead of yaoi), but the plot is done so much better. The updates on it are slow but if you wanna give it a read it's here http://www.mangago.zone/read-manga/saiyaku_wa_boku_o_suki_sugiru/
Don't hate the MC just because he couldn't accept this whole ordeal. It's not easy to accept something like this. Unlike the Ml, he has no memory of his past life, so he has to actually process the information. You actually expect him to be empathetic in a moment like that, especially someone he doesn't care for?