Yta... Fwiw, I'm really torn on this one. I see both sides of the issue. On the one hand, I get the people saying we should respect people's name choices, it's just a name, and weird doesn't equal asshole.

The thing that pushes it over the edge for me is the it's the only name that speaks to you situation. There are literally endless possibilities. There has to be some lack of self awareness here for the things you say to make sense. It would be one thing if you were like, "I understand why my family thinks it's a bit wierd, and I'm sure there are other names out there, but here are xyz reasons I still feel this is the right thing to do."

But instead, you seem to have no understanding of why this would bother or wierd anyone out. Which makes me have serious doubts about your ability to read if your SIL is truly OK with it or if she's just placating you because A) you've worn her down. B) she's just not good with confrontation or C) she's genuinely afraid of you because this had creeped her out.

It's not wierd or assholey to want to change your name. It's not weird or assholey for it not to be some name associated with your family. It is definitely weird and mildly assholey to choose literally one of the only handful of names in the entire world that would cause confusion and weirdness for your family. There are so many options and there has to be a bit of assholery inside you to be so rigid on your decision that you must choose the one name out of billions of options that makes things potentially weird and confusing for your family.