"a trophy wife is usually considered to be unintelligent, sometimes even a bimbo." - Wikipediaより
"A spectacularly beautiful wife. With the implication that she has little other than her beauty to offer the husband. I.e. that they have little in common, and she probably has few brains. He has married her to show off, she has married him for his money."
- http://www.answerbag.com/q_view/403260