its mostly about wanting to have someone to control. since hes the next head, she wants to control him for the power he'll have. if she could have her own kid then she'd be obsessed with them instead, but shes infertile and her relationship with her husband is supposedly bad #－.－)
It hard explain but let me give some example based what i think of mother try to do
mother want control son who will be Ceo so she can be powerful woman in company not his wife.
or another example, queen don't want give up her position when her son will be king that mean wife will be queen. While she lost her power position.
so step-mother goal that make son feel like he is alone in world that he will seek her help. when she set that way.
Soooo.... What's the moms deal? Does she have a thing for her step-son? I'm not understanding her obsession.... someone help please?