I'm new here and male. I'd like to start by saying I feel there is a lot of wisdom in what the other posters have been saying.
It takes two to make a relationship and I'm not seeing that he's putting a lot into it.
It is completly accurate that what's happening may be revealed with what he is doing on the net. Be sure you want to know the truth about it, because it could be painful what you may find.
You sound like a lady who really loves him, but you can't save him unless he is prepared to own his own issues and work on them. I do not want to hurt you, but my heart suspects he may be involved in a relationship that is not platonic.
The other posters provided real wisdom. You have to look after yourself.
I have not disclosed much about me yet, but I hope when I do I'll get the caring, frank support that the others here have offered you.