What happened Simonetta Vespucci?

Simonetta Vespucci died just one year later, on the night of 26–27 April 1476, probably from pulmonary tuberculosis. She was only twenty-two at the time of her death. Her husband remarried soon afterwards. The entire city was reported to mourn at her death and thousands followed her coffin to its burial.

Did Botticelli paint Simonetta and Giuliano?

Botticelli painted the standard carried by Giuliano at the joust in 1475, which carried an image of Pallas Athene that was very probably modeled on her; so he does seem to have painted her once at least, though that particular image is now lost.