If he suffers from depression and anxiety that could be a big part of the problem. It was depression that caused my husband to act the way he did, and he was the only one who could change that, either through medication or one day he just snapped out of it. It just happened to work out that I had to leave for two months for a job in another town and when I came back he was better, but there was a "get yourself better or else" involved, and if he hadn't been better when I came back i would have gone through with the or else part. I didn't want there to be, but I got to a point where I couldn't deal with it anymore.

There are several options. Here are some of the things we tried, they didn't all really work well, but that was us, this is you, they could work. Some are more extreme than others, its just a matter of your level of frustration.

*Have you tried a counselor or psychiatric help?I would suggest couples and individual counseling.
*Try setting aside a period of time each week where you just snuggle and make out and see what happens. Make it a time where you to can just relax get comfortable.
* if he doesn't already know that you are having and online relationship let him know.
*Try sending dirty emails to him or leaving notes in the morning about what you will do to him when he gets home adn see if you start the arousal factor in the morning and he has to anticipate it all day, if that helps get him going alittle more.
*When he doesn't feel like having sex, lay down in bed and masterbate loudy. this may arouse him. and then its your choice if he does get aroused you can either let him join you for fun or tell him no and let him feel the same denial factor you feel everyday.(thats the spiteful way, which i did once when I was really pissed off)
*As someone suggested before discuss the option of and open marriage, sometimes something that is that drastic is enough to get them to wake up.
*short term separation, if there is anyway for you to take a month "vactaion" and go stay with a friend or family member. Removing yourself from the situation can cause you to have clarity and it can again jolt him into waking up and realizing that if he doesn't do somethign he might really loose you.