I’ve got a good friend who married a Doctor

I’ve got a good friend who married a Doctor.
One day he told her: “You need to do something to spice up our love-making”.
Soon thereafter, he came home and found her in bed with another man who is also an M.D.
“Why?” asked her husband. “You said I needed to do something to spice up our love-making;
I just wanted to get a Second Opinion”, she replied…