Once trust is gone it's impossible to get it back. Reading his text messages, Facebook page and looking through his phone is no way to live. Transparency in a relationship is too little too late once trust has been broken. Following a cheater around to "keep him honest" makes his honesty your responsibility. You will never know if he's being faithful because he's afraid of getting caught again or because he's really changed. Have some self respect. You deserve better than being his keeper.