No state wants to keep you in a marriage you don't want to be in. So, if you don't think you can afford a divorce lawyer, you have options.
Every state has a legal aid office. These offices provide free or discounted legal services by attorneys in the state for a variety of legal issues, including divorce and domestic violence situations.
You could also request a waiver from your state for the filing fee. Every state has guidelines allowing people to request a full or partial waiver of filing fees and court costs based on their income and other financial circumstances. Applying for these waivers could make divorce suddenly much more economical.