Who is Don Johnson from I'm with the Band and what is their importance?

When Pamela first meets Donny Wayne Johnson, he is a struggling actor fighting for parts. Pamela describes him as unlikable, self-centered, and conceited. None-the-less, the couple eventually moves in together. Their time was tumultuous to say the least, and Johnson seems a frightening character..... abusive, controlling, and rude. He even expects Pamela to accept his teenage lover..... a very youteenage lover. ng