Well, my DSD is only 11, but we've talked before about how nice it is for her to have so many adults that care for her, that she has 2 families and some extra grandparents. I've also told her that even though I love her very much I will never be a replacement for her mom, I'm another person that loves her, just like other family members do. I do pretty much care for her as I would a child that I gave birth to, after all, while she is here I am one of the adults that is responsible for her. She gets hugs, kisses, and discipline from me, just like she would from her biomom, and I go to some of her school things (not all because that is an hour away) and the birthday parties too. However, a lot of 'decisions' do not come from me, though I always give DP advice about what I think. This was the way DP and I agreed together to be from the beginning. It sounds like you have a good relationship with their mom, can you talk to her about this at all? See if she has any suggestions? Is the relationship good enough that the two of you can sit down together or separatly with the older/teen kids and reassure them that it's ok for you to love them too?