So the MC aways transmigrates into bodies which loved one person and destroyed their life because the person they loved liked someone else. That's because the ML was actually in love with MC and he was like... the younger brother of some celestial emperor and MC was in love with some other guy who then killed MC making ML start a rebellion and have his soul shattered to pieces and ML's older brother making the system for MC.
It sounds a bit like “Holding Onto My Man,” but I’m not far enough into the story to know much of that stuff.