The part I’m struggling with is the idea that your sister’s infertility is simply “other people’s issues” that you don’t have the capacity to deal with.
I understand needing to protect your emotional wellbeing during a difficult pregnancy, and nobody should be expected to absorb someone else’s distress constantly. But this is your sister, and she has apparently been struggling with infertility for years. I can understand why she would feel deeply hurt if, after finally opening up about something so painful, she was essentially told that there wasn’t capacity for her because you needed to focus on your own journey.
Infertility and pregnancy loss are very difficult and all consuming. You can be genuinely happy for your sister and still be devastated by what is happening to you. Those feelings don’t disappear because somebody else is pregnant.
I also don’t think she should be criticised for not telling you sooner. Infertility is deeply personal and often involves years of private grief, and people disclose it when they are ready. The fact that she told you after you became pregnant doesn’t mean she was withholding something you were entitled to know.
You don’t have to become her counsellor, and you are entitled to say when you don’t have the capacity for a particular conversation. But I think there is a difference between setting a healthy boundary and deciding that, because you’re pregnant, you have a free pass to focus entirely on your own happiness while your sister puts her pain aside!
And honestly, I can understand why her comment about “if it were me, I’d be there for you” hurt you — but I can equally understand why she said it. It sounds like she was trying to tell you that she felt abandoned by someone she expected to be there for her.
I don’t think either of you is necessarily wrong for having difficult feelings here - if you have had a difficult pregnancy. But I do think your sister’s pain deserves a little more empathy than calling it “other people’s issues.”