I think that you have to decide what's really important to you. You should confront and fix your current problems before you pursue something else. If you are going to end your marriage, then you should probably do so before you emotionally cheat on your husband.
A little late for that but that's the problems that most of us. We don't want to try and fix something, we kind of just let things go in hopes that they fix themselves. But that rarely happens.
I'm not saying that you are to blame for everything, and your husband might be impossible to deal with and lack any empathy. But you have to take responsibility for what you are in control of. What you did with this guy was wrong and you are just emotionally detaching from your marriage so that when it finally hits that inevitable end, you will have no feeling for it anymore. It's a defense mechinism but it is not the way to handle problems. It's wrong.
Regardless of how you feel, you have to figure out what you want to do, and just do it. Take your problems head on and deal with them. I can't help but feel that the problems you have in your marriage are just problems that aren't resolved and swept under the rug and they just keep coming back bigger and bigger each time.
Waking up next to a beautiful girl,
Step outside and say hello to my beautiful world.