Fell in love with a boy name but there is one problem..

So I am currently pregnant with my second child, my daughters first name is Maribel, if she was a boy I wanted to name her Mateo.. weeeeelll before she was born I found out my boyfriends nephews name is Mateo and I’m broke because I was IN LOVE with that name I’m telling you I cried when I found the perfect boy name. Any who my boyfriend has never met his sister nor his nephew (they live in Mexico) but his mom talks to her everyday. Do you think his sister will be upset if we have a boy and named him Mateo or should I just forget about the name I fell in love with and find a new one..? I’ve also looked everywhere for another boys name for this exact reason and I can’t seem to find one that melts my heart like Mateo did☹️