Very very difficult....
ChristinaB made a lot of good points...ajs I know it goes with out really saying but do think long and hard....

I had a first marriage many years ago and gradually over the years of it became unbearable...the unhappiness...the loneliness as we drifted apart...and the utter sickness in my stomach when sometimes he would try to touch me....and when hearing his key in the door the disappear that would consume me.....I didn't even LIKE him anymore..
Thats when you KNOW its best to leave...