As far as I remember that MC was a pretty ruthless one...he even dug his heart out to prove something, I don't remember anything more...but I can't for the life of me remember it's name and it's giving me a headache...
I don't think this is what you want. But this kinda reminds me of something. It's not even a BL. MC is an idol or something. MC has a sad and difficult past. His mother was abandoned by his father who remarried to another woman. His father is an asshole who only cares about money. He even got involved in the plot of someone who wanted MC heart. MC father came to a tv show and demand MC to donate his heart because he has a disease. So MC asked his fans to close their eyes and count to 100 (maybe? I forgot). And in front everyone MC dug out his own heart and gave it to his father.
Is this Entering a Split Personality? As I remember there's an arc where there's a stand-off about whether the MC likes the ML and MC's heart is ripped out
Is it: Game Loading Because in one the mini arcs in the last big arc the MC ripped his heart out to prove to ML that he can't keep him there (or something along those lines) since ML locked him up. Iirc MC was the king of beasts(?) In that arc. And there was ML x2 because MC accidentally touched two of ML souls at the same time. So the soul world's got combined. Hopefully thus helps, even if only to cross a title off your list
The MC dug his kidney not heart. The MC had split personality. One of the personality was doctor. This is a non cp qt and has another continuation book.
umm.. The only thing that I can think of would be: Heroic Death System Arc 2 - My heart beats for you (Ch. 10-19) and Re-Arc 2 (Ch. 114-118) MC... is in love with ML's younger sister, the girl gets together with MC's older brother, she has a heart disease and needs a heart donor, MC has a brain tumor and in the end donates it to her to prove his love to her, but he doesn't literally dig it out. Aside from that, the only other novel with a "similar" plot would be Quickly wear the Face Of the Devil Arc 14 - Twins of different fates (Ch. 14.1-14.16) where his twin sister has a heart disease and MC has the matching heart, thus is brought back by his sisters' adoptive family.... In this arc, MC doesn't want to give her anything, but she is the one who literally tries to do the operation on him herself... But I don't think it's QWTFOD... do you perhaps recall something else?