1
general::
Lovers often face difficulties, as in Every time he tells me that he and his wife are fighting, I say the same thing? you know about the course of true love. The full term is a quotation from Shakespeare's A Midsummer Night's Dream (1:1): "The course of true love never did run smooth." Over the years it has become so familiar that today it is often shortened, as in the example.
American Heritage Idioms