The one I'm looking for is a BL. Don't pick on me!!! It's one of those System novels. One of the arcs talked about the MC being in the business industry and having a possessive ML. When the MC moves on to a different world, he leaves the body behind. The ML becomes detached and delusional(?), acting as though he's still alive and talking to the corpse. Don't judge me
It is The Strategy of Washing Clean a Slag Shou, it’s the first arc - The President’s Unfaithful Lover