Marriage problems

Hi, I just signed up and I'm not sure how this all works, but I'm looking for advice and guidance on what to do in a failing marriage. My wife and I have been married for 25 yrs. We have 3 kids (2 in college and one a senior in high school). We have had problems for years. I question our marriage and if we should get a divorce, this really upsets my wife. She says that divorce is out of the question and I need to heal that hurt from bringing up divorce, but she will not change anything on her end. I have gone to counseling about 5 times in the past few years and she will not go. I "hate" arguing and it seems that is all we do, we just keep going in circles. I feel sick almost all the time. I don't want to go home from work because of fear of more arguing. If we are around friends, we both act as everything is ok, but I'm almost scared to be alone with her. My "fuse" has gotten so short with her, she will start in on how I hurt her with all the times I questioned a divorce and she will say I need to heal that before she will do anything....things just explode. I still love her and would love to make things work out for her and I and the kids, but I'm at a loss. I don't know what to do anymore. My home is not a home to me anymore. I'm tired of the feeling sick, the pain and just all of it. I'm not sure when enough is enough and divorce is the right thing to do, or is there something that can still be done? Has anyone been in this situation? Suggestions?