Looking for a specific manga

Looking for a specific manga cuz I don't remember the damn name no matter how much I try to remember. -_-

From what I remember it is a "get transported into the villainess' body"
-she is married to the ml already
-has a step son who basically grows up to kill the father (I think in the original story but she wants to change that)
-fl wants to become a good mom
-she had red hair and son/father had blonde hair
-son trains to become the head of the family
-son appears to be innocent in front of mom
-son drinks poison at one point too and also has to play with the other Noble children when they all go to a party at one point in like a fight happens between the children or something

Please tell me if you know what the title is thank you.ヾ(❀╹◡╹)ﾉ~