Damsels are almost always aggressive or eventually become that way. I've always heard that the ones with stripes or spots are the worst. I would really try to avoid getting it if at all possible.
A 60 limits what fish you could add. Off the top of my head...Tangs are out. The really small angels (cherub or Flameback)...dotty backs usually can hold their own...some of the Hawkfish....some fairy wrasses...some clowns...maybe a dwarf lion fish?
I agree with the Todd,if you can try to persuade your wife to chose another fish do it...I wanted a Domino or Yellow Tail to start with and then I did research that changed my mind.One they are very aggressive and and two they are as pretty when they are adults.The big thing was the aggression because they become more aggressive as they get older.If she is animate about Dominos aadd it after you have cycled the tank and added your peaceful fish first(if any).There are hardy and peaceful fish suited for fish in cycling. A good site for info is Aquarium Fish: Tropical Freshwater Fish and Saltwater Fish for Home Aquariums . Good luck! Hope this helps.