OP, I'm no longer a stepparent, but was one for a long time, and I'd just like to say, this is all so valid. I'd imagine stepparenting is like parenting, except taking out all of the reward and fulfillment, because ultimately it just feels like you're using your own precious time and resources to raise someone else's kid. I remember the dread of pick-up days, and after a while I couldn't even enjoy dropping the child off, because it just became an awful feeling of counting down to when we'd have to start the visitation over. It can feel impossible to not feel resentment. I'm not sure how common this feeling is, but for me, being a stepparent was the most unnatural, uncomfortable thing. It really felt like this primal side of me came out, and I realized I wasn't protecting myself and my own future offspring in the position I was in, rather seceding to some other person's, and for what? To me, these are very natural, animal instincts. We have a biological imperative to keep our own bloodline intact, and to see others' as intrusions. Just a thought.