Take some time to be alone and think. The question to ask yourself is:
Will the quality of my life, as I desire it to be, be enriched or eroded without him?
In other words, picture your life in scenario after scenario without him. What would going to a good movie be like without him? How about when you hear that noise in the house that turns out to be nothing - better with or without him? Handling the flat tire on the car? When you just need to talk?
If you can envision managing these situations without him and feeling good about it; or, you envision them with someone else entirely, then a divorce may be the answer.
However, I wouldn't do anything without giving my marriage another try - a really serious try. Marriage is a serious institution and not to be thrown away lightly.
Good luck whichever decision you make.