In the novel, I think he loves his ex till the end. But in the manhua, he ends up falling for the doctor and I believe his last words are I love you to the doctor.
I read somewhere in the novel that what he did to the doctor is to repay for his kindness and love. He tried to be affectionate to him, and appreciate him. Thats the least he can do. Also the doctor kinda resembles his ex-lover old self before he became successful like how he care and love him.. seriously aaaaahh everything about MC and the doctor is so bittersweet :'( sorry for saying too much
Spoiler much
Many of the comments already reveal the novel and the manhua raws. Sorry for spoiling it for you, but I wouldn't read the comments if you don't want to be spoiled.
And the doctor is clearly aware of it himself. The uke just called his ex's name (Jiang) in his sleep and the doctor just embraced him even more affectionately and pretended to be Jiang to assure the uke saying "brother Jiang wouldn’t go anywhere" :')
I get the impression main character isn't in love with the doctor. Seems deep down he likes the seme and probably will forever. I think his feelings for the doctor is more based on the fact that he's dying and hasn't felt proper affection from the seme in years. What he is in love with is the love he is receiving from the doctor, not the doctor himself.
Thoughts? I honestly don't support main character with anyone at this point, just feels like something is missing in this story.