It’s canon that William Afton is bisexual. Scott cawthon confirmed.

Scott cawthon has revealed some Interesting, although not very much useful lore after he officially retired. One of these things is that it is canon William Afton, AKA purple guy is bisexual and before marrying his wife, and also after his (also confirmed) divorce he was dating Henry Emily. He even proposed and they were engaged. Sadly William died a few weeks before the wedding.