According to my 5 year old, these butterflies love each other. I love my camera for getting such an awesome shot. Look at the eye of the top butterfly. These are Cabbage Whites on the leaf of a violet. They had fluttered about together before landing here.
The Butterfly Book by Donald and Lillian Stokes explains how to tell the male and female apart. The female has two spots on her forewing while the male has only one.