A usually young woman, not necessarily a gold-digger, who is married to a much more older man with power, wealth.etc
Those women are usually at home, 24-hour luxury, and with the children. Sun-bathing, rich friends socializing, -just enjoying the wealth and producing his children are her job.
Elvira Hancock from the 1983 film Scarface is a great example of a trophy wife
Ginger McKenna from the 1995 film Casino is another.