A family member stealing the baby name your using in memory of your husband's mom who passed away

Rae
I'm so mad! My husband's cousin is having a daughter. Before she was even pregnant, we always discussed or little girls name and the middle name is after his mom who lost her battle to cancer. She " forgot" . I'm currently pregnant but don't know the sex yet. She just found out hers is a girl. I even screen shot the convo that her and I had just to jog her memory and she was just dumb about it. I'm so hurt. We miscarried a month before she got pregnant and I'm only about 8 weeks along now. It's like she knew but now is choosing that name, not in memory but it's the name of one of her favorite tv characters.. She is trying to pass it off in memorium. I'm so frustrated. What do I do? Talking to her is our of the question because she flips everything. She is not level headed.. She is very selfish.