Looking for a evening gown/tuxedo to match on cruise?

Me, my family, and my boyfriend are planning to go on our first cruise in September. Me and my boyfriend decided that on dress night, we want to match. Where can you find a evening gown and a tuxedo that match? Also I'm wondering do the men have to wear tuxedos. I know the girls have to wear evening gowns but I wasn't too sure what the men have to wear other than they have to dress up too.