I think GBC was terrified of Allison and Toni running into each other at the conference. His lies to Allison would have been exposed and I think he thought divorce was a real possibility. Divorce would have cost him his business. He would no longer be father-of-the-year/business-man extraordinaire. I assume the 'presidential' positions he held were elected? His business partners would have found out that he'd been lying to them and ditched him. His family would have berated him for being so stupid. He would look like someone losing control. I am convinced that with all this in his mind, he killed Allison to protect his image. I wonder what's worse to a narcissist like Gerard. Having his professional and personal life unravel in public at huge financial expense, or go to prison for murder and spend the rest of his life denying it?