My thought on Jing and YSQ.
YSQ is the inner personality of TSJ Jing. Jing has always been YSQ deep down . This is why his household staff love him so much. What TSJ went through with Hou tortured brought his YSQ personality out.
It is because she was already attracted to YSQ personality that she fell in love with TSJ.
YSQ is TSJ without the extra baggage from TSJ 's life ( family, Tushan clan, responsibilities).
My thoughts on Hou.
Very simple really. Regardless of how TSJ's mother treated him, if Hou had realky loved TSJ the way TSJ loved him, there is no way in hell he would have done what he dud to him : torture, take his fiance, have sex with her, use her to humiliate His little brother, tried to kill him.
So regardless of how Jing's mother treated him she never went that far with him. Hou had never liked his little brother .
If he had he never would have done those things to him. He never regretted them. Never felt sorry.
He has always wanted to be the true heir since he is the eldest. He resent his position since he is the son of a maid. He married a maid. When he actually get a "descent" woman. She us TSJ' fiancee.
So all in all, Hou hated , was extremely jealous and deeply envious of TSJ and what he present deep down .
This is my 2 cents