It sounds like you are in pain and keeping a lot of chaos in your life as a way to avoid that pain. I think that, before you make any radical life-altering decisions about your marriage, you need to get into therapy and build your self-esteem, as well as to start unraveling why you feel the need to cheat, and why your relationship with your husband has devolved in such a way. A caring but objective third party can guide you in making better choices that do not hurt yourself and the ones you love.
The world opens up... when you do.
"Oh, oh, can't you see? Love is the drug for me." ~Bryan Ferry
"Love and the self are one . . ." ~Leo Buscaglia "