Stepparents are often placed in a difficult position, unsure of their role in their stepchildren’s lives. They’re expected to do many of the things a mom or dad would do, without the title of’ mom’ or’ dad’. It’s entirely valid for a stepmom to fully step into the role of being a mother to her stepchildren. It’s also valid for a stepmom to not be seen as a parental figure at all, functioning more as a mentor or a safe adult their stepkids can confide in without making major (or minor) parental decisions. Every family is different, and the most important thing is that the kids are comfortable with the new adult in their lives, regardless of whether that role is parental or not. 

When there are half-siblings living together under the same roof, it can be difficult for them to see their stepparent treating their biological child differently than they treat them.