Even though I have not been a legally engaged stepdad for almost three years, I still worry about my kids. I still wonder if they are upset about something that happened at school. I still wonder if they need help with homework. I still want them to go to the doctor and dentist, just like my parents did after I moved out.
I know their Mom loves them and is smart enough to keep them safe and happy. But I know I put them first whenever I could for five and a half years. And I believe that it takes a village to raise a child. I also believe that continuity is healthy.
When a step parent divorces they are considered free of this responsibility. And if the step parent wants to help their kids because that's what they have devoted the last five years of their life to, their previous commitments are considered irrelevant unless they can prove the biological parents are bad parents. It doesn't matter how much the step parent benefited the step child. It only matters how the biological parents feel about the child's relationship with the parent.