orson hodge

I'm trying to remember why Bree and Orson separated in the first place.
I remember: Bree left Orson in season 4 because he ran over Mike. Orson decided to go to prison. Orson got out of prison and couldn’t find a job. Orson forced Bree to make a potroast. Orson got Bree high on sleeping pills. something happened. Orson blackmailed Bree? Bree had an affair with Karl. Karl died in a plane crash and Orson was paralyzed. Bree felt guilty, and took Orson back. Sam appeared out of nowhere and blackmailed Bree. Orson found out about Andrew’s hit and run and left Bree. Orson got a new girlfriend who broke up with him while Bree was with Keith.  Seasons 5-8 are a huge blur to me. What caused Orson to blackmail (?) Bree, leading her to have an affair with Karl?