Cognac, I'm sorry this situation isn't getting any better. Try to get him into counseling with you, if you want to salvage the marriage. I mean a trained, professional, impartial counselor--not the elders (though according to the Top Secret Elders' Manual they really ought to have some strong words with him, the way he's been misbehaving).
Avoid logging into his personal email and Facebook accounts--anything that clearly isn't a joint account with both names on it. A divorce lawyer could try to use that against you (invasion of privacy, etc.). "Do unto others", etc.
Take care, and do what's best for those children.