There was this one historical manga where the MC got transported into another world. The M...

There was this one historical manga where the MC got transported into another world. The ML was originally married to the MC, but the ML's concubine was the one he actually loved. The MC' family hates her, but her grandfather loves her.

There are a couple of scenes I remember:

1. The MC made a deal with the ML: Since the ML's concubine was very sick,(she isn't really sick, she just fakes it to get attention from the ML) the ML forced the MC to get the her family plant to helped cure her disease. The MC agreed on one condition: the concubine was not allowed to set foot near her. The ML agreed which made the concubine mad because she couldn't plot against her.

2. While hunting, the ML got drugged by the MC's sister. The MC's sister almost got her way with the ML, but I think the MC showed up just in time. He woke up from the trance when he saw her, but he blamed the MC, saying it was her plan so she could get out of the marriage.

That's all I remember. PLEASE, HELP ME FIND THIS!!!

(this is someone else's post but no one is replying and i would like to help this person and i would like to know the title of this as well)