Leaving husband

I don't know what to do. I know that I want to divorce my husband. He is mean and gets extremely aggressive and physical when angry (not hitting, but pushing). He can be so nice and loving and our sex life is amazing. However, our views on things in life have changed since being together. We're no longer compatible mentally in my eyes. We've been together 5 years, married for 3, and have a 6 month old son. I want to leave but I currently don't have a job because we only have one car and I watch our son whilst he is working. Also, when I start to make a plan to leave him I start to feel guilty. He has no family. Myself and his son are the only family he has. So it makes me think he might commit suicide or do something crazy. I have one more year of my BA in college then a year of an internship before I have my real job. Any advice?