I completely understand what you are feeling. I talk with my therapist about this same subject often. I try to talk to my spouse but he really just tells me I need to get over it. I'm angry at my mother for treating us very differently also. There was my older brother, my sister who is 13 years younger than my brother, then me who is almost 3 years younger than her. I'm the youngest. My brother being the oldest had it the toughest I'm sure. He basically grew up like an only child for the majority of his childhood, and being the first, that's usually the one that parents make all the mistakes with. Now I'm not including being angry at my father in this because my parents are from Scotland, and men especially from that generation from Europe, did not have anything to do with raising children. The women did that. I have other issues with my father though. Anyway, my mother always treated my sister like she was so much more important than me. I tried so hard to behave, to get excellent grades, to do everything I could to get attention, but my mom just always showered all her attention on my sister. Even when we became adults, it was still the same. My brother said once that he wondered if they even knew that I was there. So that tells you it wasn't just me imagining it. I haven't figured out how to let this go either. But, if you do, let me know! I could use the help also! Hugs!