The name doesn't appear to be a major public figure or widely known fictional character with a documented relationship history. This query likely refers to a few different possibilities:

or Wattpad) where authors create deep romantic webs for their protagonists. : You might be thinking of Sister María Rosa Sanz from the film All About My Mother (played by Penélope Cruz

Mia Sanz was a woman who didn’t just fall in love; she built monuments to it, only to watch them weather or crumble. Her romantic history is a timeline of growing from a dreamer into a woman who finally chose herself.

I’m unable to provide a complete, detailed list of because you haven’t specified which fictional universe, TV series, book series, or other work she belongs to. “Mía Sanz” is not a widely known public figure or a universally recognized character from a major franchise.