Ok, you've put your cards on the table. If it were me (and this is where you have to decide what's right for you), I wouldn't bring it up again and I wouldn't snoop. If he brings it up and you choose to have that convo, go ahead. You have alot more contol than you think. The deal is, you control you. Only you, only your actions.
You say you feel like it's you who will be filing. Why? If it's what you want, by all means. If it isn't, why would you? I get it, I am asking the questions for you to think about.
When you say expose the truth to your family, I would caution you against slamming him. Just my 2 cents.