When my mother was pregnant with me she didn't know if she would have a girl or boy but she told her mother what the chosen names would be. My grandmother was shopping soon after and was so excited and proud she mentioned it to a woman who my mother went to school with, who was never my mother's friend, but a nasty person. It turns out that she was pregnant at the same time and gave birth to a girl one month before I was born. She named her daughter with my name!
My mother was furious and when I was born my parents were at a loss for a name. So, for ONE YEAR, I was "baby", "sweetheart", "sunshine", etc... I had no name! They finally came up with something that they thought fit my personality and was even better, and it was. I pity the other woman and the child she had. How would you feel if you knew you had someone else's name? Someone who is incapable of coming up with something on their own deserves pity.
If I were you, I'd use the name if I really wanted to, it was yours first after all and after your husband's name too. I'd also mention it to everyone when meeting them, as a matter of fact, to let them know that the other parents liked it so much they copied you. If you don't want to bother with that, then come up with another even better name, and never trust her again.