My (40M) sister (39F) recently started a discussion in our family group chat about planning a summer get-together. My wife and I talked it over and decided that while we appreciated being invited, we weren’t interested. Last summer, we went on a beach trip with my parents (mom and step-dad) and sister’s family, but it ended badly.

During that trip, my parents were upset with me after I suggested we be included in the planning for future trips. They preferred to plan everything themselves and then inform us, expecting us to adjust our schedules. My mom and step-dad are in their 70s and don’t handle suggestions for changes well—they tend to see it as criticism. My mom also mentioned that my sister’s schedule and needs take priority because she has kids and that they wanted to make sure her husband could attend to help their marriage.

I decided to call my sister directly, thinking it would be easier to talk things out than put it all in writing. I explained that my wife and I weren’t feeling up for another trip and shared how last year’s trip left us uncomfortable, especially after the discussion with our parents. She asked for more details, so I told her about the comments Mom made about planning the trip to support her marriage.

Apparently, this was brand-new information to her. She asked what I meant, and I said something along the lines of, “Well, you know, because Mom and Dad aren’t big fans of your husband.” (in hindsight bad road). She hung up after that.

For context: Over the years, both my mom and my biological dad have shared their opinions about my brother-in-law with me. My dad has said he’s frustrated that BIL doesn’t treat my sister like a princess or isn’t fully dedicated to her. My mom has expressed that she wishes he were more present for both my sister and her kids. I assumed this was an open secret since they’ve talked about it often and their attitude toward him isn’t exactly warm. I thought my sister would already have some idea of how they felt.

She called me back today, furious. She had spoken with both my mom and dad, who denied ever saying anything negative about my brother-in-law. My mom also denied saying the trip was planned to support my sister’s marriage and accused me of lying.

My sister then asked why I would say something so mean and inconsiderate. I told her I wasn’t trying to hurt her—I genuinely thought she already knew. But things escalated, with her yelling and cursing at me. I tried to stay calm and suggested we take a break and revisit the conversation in a week after cooling off.

Later, she sent me a text asking me what were you even trying to accomplish by telling me those things and "Please be more thoughtful and kind in your delivery in the future.”

Now, I’m trying to figure out how to respond. I want to approach this in an open and non-confrontational way, but I’m unsure how to proceed. My wife thinks my first instinct—to simply repeat the facts—isn’t the best approach. I’d love advice on how to de-escalate this, make my sister feel heard, and avoid further conflict.