[fastaguy88]

This conversation might be more helpful if you had it with other faculty, particularly the Director of Graduate Studies, in your department. In general, Departments want their graduate students to graduate (statistics on graduation rate are used to justify training grants), and to be successful in their later careers. And Director's of Graduate Studies have a useful historical perspective; they may know that your advisor has had a history of problems, or that your situation is unusual and bears looking into.

There are almost certainly resources in your Department to support you and help you with your decision. You should explore them.

You should also understand that you can ask for letters from other people in your department, in particular from your thesis committee. While it is not ideal, it is not unheard of for students to provide letters that do not include their advisor. The more you interact with other faculty, the better in your situation.