Forgot bl name

So. Its heavy. Its about an son whose not related we find out, who likes his older brother and they are in an old 1800 family and the dad killed his wife's lover when she tried to run. The dad beats the son because he's born from his wife and her lover. The ML is a man who sleeps with the MC but we find out he actually loves the MC brother cus they went to school together and the MC ends up with his brother(whose not his brother)