Please go to my user name and "view posts" and read my very first post. You sound a lot like me in many ways, specifically that my husband and I never had that "spark", but yet, I was able to find the spark in me with OM's.
I believe my marriage could have been saved, but there were so many things going against it - and I am divorced now. My post is a long story, but its all there. Please read it and decide if you see yourself at all (I don't really know how to link it directly on the screen like others are doing).