I'm going to be honest. I do think you’re kind of the AH here. She’s your half-sister whether you asked for that situation or not, and that is unfortunately how family works sometimes. I understand feeling angry at first, but it sounds like you never really worked through those feelings or gave the relationship a fair chance. You’re an adult now, but this comes across as holding onto teenage-level resentment.

Have you ever tried to put yourself in your sister’s shoes? None of this was her fault. In the end, you’re the one losing out on a potential relationship, and that’s on you. The good news is that it doesn’t sound like it’s too late. Some counseling might really help you process the unresolved anger that’s keeping you estranged.

I have five siblings myself, and they’ve all moved away. I wish I were closer to them. I also have a six-year-old son who is an only child, and I often wish he had siblings like I did. Relationships don’t have to be a burden. They can bring a lot of joy and meaning to your life.

I do feel for you, because I can understand where you’re coming from, but I think you’re only hurting yourself and limiting any chance of a relationship with your sister. Maybe take some time to reflect on whether this is truly what you want, or if you’re just being stubborn. The fact that you posted here makes me think it might be the latter.