Please help me find this

I cant remember much bc i read it like 2 years ago, just remember it was like one of those promotional 1 chapter manhuas which promote the novel or something and it was on here.
I think they were enemies at first? maybe a war or something? but mc gets crippled by ml or gets really sick bc of him or both and then they become lovers somehow?? He really regrets it and hes doing whatever he can to cure him. Its also like those ones set like way back, historical type of setting.