as a means of venting privately in an anonymous fashion. I totally get why you would feel hurt, but I can guarentee you even though they were personal and private things, he did not mean ill will towards you. In fact, the impression I always got from Joe was that he loved and respected you tremendously. He put himself down on many occasions, saying how he didn't deserve you, way better looking (obv sorry Joe), etc.
As you well know, life is a ****. There are many stressors and tension constantly building inside of people. Just like brad had said about being a little socially awkward, the internet provides a means for people to act and be a different personality that life or social disorders prevent them from being. I advise the both of you to seek counseling asap, as I believe that will open BOTH of your eyes to things you both are currently blind too. It is a two way street as you said, and I'm sure you realize their are probably things you could be doing differently as well