With Cupid's arrow ready to fly tomorrow, there is a high incidence of two romance oriented Nash quotes on the Blogisphere: 1) Candy is dandy, But liquor is quicker and 2) "To keep your marriage brimming, With love in the loving cup, Whenever you're wrong, admit it; Whenever you're right, shut up."
The former presumably being offered up to those looking to progress their relationship to a meaningful stage that evening and the latter being offered as guidance to those looking maintain marital bliss.
Here are a couple of examples: Thought for the Day on news aggregator Arcamax focuses on the more wholesome of the two recommendations. As does the UPI almanac and 'Maddening' in her live journal entry
In London's Independent an article called "Love bites: The naked truth about aphrodisiacs" cites Nash's view on liquor vs. candy.
Of Course Nash also wrote "To my Valentine" which you can read here.