My dad is addicted to gambling and trapped in a loveless marriage with my stepmom!?

I can appreciate your sentiment. Please know that it is NOT your responsibility to make sure that your dad is happy. That's HIS job. Being happy doesn't necessarily ensure that someone won't relapse in their addiction. Sadly some people relapse when they are absolutely giddy. Besides, your dad is an adult and has to learn at some point how to function when he is either happy or sad. He has to learn to manage himself regardless of his emotions. Until he does, his recovery is superficial at best. Love your dad with all your might...but know that ultimately ownership of his decisions is his own. Best of luck to you.