@outtacontrol,
I suggest counseling. Seriously. Couples counseling if you can, or go alone if you must.
Figure out what is missing in your life that you feel the need to do this. Prepare in case ending your marriage ends up being your destiny (and, from where I'm sitting and what little information you've provided, that seems like the kindest and most honorable thing to do for your spouse, a person you purport to love). Cultivate some inner resources so that, in your life, when you're bored or depressed or your self-esteem is low, you don't hop into bed as your first resort to handle such feelings.