C'mon... DH is a soap, and on soaps, things are rarely that cut-and-dried.

Here's my speculation: Tom's daughter Kayla, taking after her crazy, bitch-ass mother, goes to burn down Rick's restaurant. Rick sees her setting the fire and walking away. The fire goes out. Rick then sets a bigger fire, allowing the restaurant to burn to the ground, knowing that Kayla will believe she was solely responsible. Kayla confesses to Tom, who takes the fall for her. He won't tell Lynette the truth, knowing that she'd go to the police with it, so he goes to jail for arson with Lynette thinking he's guilty. Cut to 5 years later; Tom gets out of jail to find Rick married to Lynette and raising his kids. Tom goes after Rick, then Rick pulls a gun on Tom, saying he's going to kill him "in self-defense," but first he monologues and tells Tom what really happened the night the restaurant burned down. Lynette overhears, and before Rick can pull the trigger, she clocks him with a frying pan. Lynette bitches Tom out for not trusting her and apologizes for not believing in him, and they get back together. Only Tom has a secret from his prison days, something that could jeopardize his marriage... The End?