Geez, why do you feel guilty about asking for time out away from the kids?

It seems that he wants his porn and he is being protective of it and is cutting you off from discussing it? I would suggest that you approach him again and don't mention the porn at first at all (because it seems that he is getting defensive) and tell him that you want to share some of your feelings. Do you want him to stop watching porn or do you just want to share your feelings about it?