Fiancée wants all black wedding party

Fiancee has all bridesmaids getting black dresses. She wants all the groomsmen to beat wearing tuxes as well. To me, this seems like too much black.

Does anyone have any suggestions for ideas or suggestions or anecdotal stories to help me like an all black attire. I would have preferred a dark charcoal groomsman color while i wore a tux but she thinks it’s too informal.

Thanks