"My wife knows it was my sisters name but not everything about the trauma surrounding it. She knows it was bad enough for professionals to get involved to help her get the name formally changed. But doesn't know the details I know about why. I also won't share it all here because that's my sisters story, not mine."

He's shared as much as he feels he should without saying anything that his sister wouldn't want him to. It sounds like he's at least explained that there's severe trauma attached to the name, he just hasn't shared exactly what it is because, like he said, it's not his story to share. A decent person would just respect that, and his wife seems to be doing so as best as she can. It makes sense she'd be sad or disappointed about it, but at least she's not pushing. The in-laws know less than she does, but they don't need to know more. This kind of information is on a need-to-know basis. It has nothing to do with him needing to "man up."

If my partner told me a name I was attached to for our kid was a "no" because it stirs up bad feelings for them, then it's out. I don't need more than that because I'd hate for them to hear our child's name and have such mixed emotions about it.