I am loving this thread! It's really good to think about these things, because like I said, I'm pretty early into stepmothering.
Mamanicki, you bring up such interesting points about kids continuing to seek what they're missing from their parent(s), rather than being satisfied that they're getting it elsewhere. What I take from your sage comments is that I'm not going to "try" to be anything to these kids. My current relationship with them is much more passive. I just am myself around them, and I interact with them in the ways that I do (playing, reading, talking honestly about whatever they're interested in) because I really like them. I'm hoping that through this relaxed attitude with them, they'll feel able to trust me and get along with me. That's all I'm hoping for right now.
I have been extraordinarily lucky so far because my skids all respond really well to me, despite their biomom's efforts to thwart any relationship we might be able to have. So maybe that's where some of my hopefulness comes from. But to clarify, I don't hope to replace their mother. I know I can't, and what's occasionally frustrating for me is that I'm NOT their mom — and, of course, that their mom could be so careless with their feelings and not seem to understand what's best for them.
Flor brought up the idea of being considered a parent by her dss, and that's interesting too. I'm not sure what, if anything, my skids think I am. We haven't really quantified the relationship at all, primarily so that we take things slowly for their sake and also because I'm not yet married to their father. The youngest one established that I'm not their mother (to which I replied, Of course I'm not, silly. And we never really had the "you're not my mom, you can't tell me what to do" phase...yet), but we haven't gotten into what I am to them, beyond dad's girlfriend. Like I said, I'm just fascinated by them and very interested to see what these relationships grow into.
I'm so glad there's a place to discuss these things with understanding, experienced women! I am the only stepmom I know. In fact, most of my friends don't even have any biokids, so my experience is rare indeed. Thanks to all of you!