So, is this actually based on the Wagners' real family life?

Just wondering if the stories that were told about the dad leaving for another woman, the mom having an affair while being sexually indifferent to her husband, and the family losing all their money in the 80's are actually true or purely fictional.

Normally I wouldn't ask this about a movie, but since the writer/director seemed to have written it *for* his real family, I thought maybe it really was supposed to be *about* their real life as well.