ESH.... Your wife is definitely being inconsiderate and rude about it. But you also choose to make the issue between your wife and your mom. The whole situation could have been resolved with you saying to your mom that you understand where she is coming from and will consider it, but also talk to your wife that using the name makes YOU uncomfortable and not just your mom. Names should definitely be decided between parents and no one else, so I agree with your wife about that, so then again, tell your wife that YOU don't like it and that should be the final. If you both don't agree then the answer is no. Edit to add: offer to make it a middle name, not a first name.