My sister asked me to hide her separation, and now every family conversation makes me lie

My sister told me in June that she and her husband were living separately. She had moved into a furnished apartment nearby while they decided whether the marriage could be repaired. She asked me not to tell our parents because she did not want questions, advice or our mother calling her husband.

I agreed. At the time, privacy sounded simple. I would not volunteer the information.

It has not been simple. Our family talks constantly. Mum asked whether my sister and her husband wanted to share a beach rental next summer. Dad asked me to help choose a grill for their housewarming anniversary. My aunt wanted their address for a holiday card. Each question required me to redirect, pretend not to know or give an answer that was technically incomplete.

Then Mum called after seeing my sister’s car outside the apartment building. I said she was visiting a friend. That was an actual lie, and I heard myself cross a line I had never agreed to cross.

I told my sister I could keep her confidence but could not keep manufacturing explanations. She said there is no difference because refusing to answer will reveal the separation. She is probably right. In our family, an awkward pause is a press release.

Her husband has told his brother and two friends. My sister says that is different because his family respects boundaries. She wants to wait until they decide whether to reconcile so she only has to tell our parents one finished story. I understand the wish. Our mother treats uncertainty as a problem she can solve through phone calls. Once she knows, my sister will have to manage everyone’s feelings while trying to understand her own.

But secrecy is changing my relationship with the rest of the family. I avoid calls because I do not know what question will corner me next. I also resent being the only sibling who knows. My brother recently complained that my sister has been distant, and I defended her with reasons she never gave.

I do not want to expose her private life. I also do not think confidentiality should require me to become a supporting character in a false version of it.

Can I set a deadline after which I will stop answering questions about her household, even if that effectively signals something is wrong? What does keeping a confidence reasonably require from the person asked to carry it?