One is GL, the other M/F, but both are historical mini dramas about the relationship between a stepmother and the child of the man she marries but doesn't love.
Both are mini dramas in which the FL is betrayed and returns for revenge by becoming a concubine of a powerful older man, becoming entangled with the ML, that man's son. Both are Republican Era set mini dramas.
Both are Republican Era mini dramas in which the FL marries into the powerful household of a man with other wives to get revenge for her murdered family and then becomes involved with the man's son.
Both are Republican Era dramas in which the FL enters the household of a powerful and dangerous man to get revenge for her family. Along the way, she becomes involved with the man's son.