“Today the phrase ‘love is blind’ is one of the most common comments people make about what people who are in love do, and how they behave. It’s what friends say in response to such things as the apparent incompatibility between couples; the silly behaviour of someone as a result of being in love; of not being practical about the consequences of the things they do because they’re in love, and all sorts of things that people do because of that overwrought condition.
Shakespeare put all that together in the simple statement ‘love is blind.’ The idea itself comes from long before Shakespeare’s time, from one of the images of Cupid (a winged Roman god of love) in which he wears a blindfold.”