You can get divorced even if your spouse does not agree with it. It will probably be more costly though as they will contest it which will increase legal fees. You could consider just living apart for a while until your spouse gets accustomed to the idea and sees that it is actually a solution. It is btter if the two of you can sort things out between yourselves as to how the divorce will proceed. If you are adamant because the marriage has been intolerable, don't back down.
Even if your spouse does not agree to a divorce, you do not need to have his/her consent to move forward with the divorce. Recognize, however, that divorce outside of mutuality will create substantial duress on the part of your spouse. This duress will eventually spill into the divorce action creating a very difficult situation for all. If it is possible, try to clearly articulate your rationale for divorce to your spouse. Seek the counsel of a therapist if possible.