What exactly do you think an 'assault' lawyer does? For that matter, what do you think a 'criminal lawyer' does?
I suspect you don't have any idea?
Whatever it is, there is nothing that restricts a lawyer to one field of practice.
Okay take it from someone who went through a divorce, it is a long struggle but one you can accomplish. First let's address the cheating...no one has to stand up in court and admit it. If you tell a judge it happened but your friend won't admit it and your husband won't it's your word against his. You can have a divorce simply because you want it. You don't have to have proof. Second I don't know if you have kids but that's the tricky part. If you do then start planning now. Things you will need to know or have. Where will they go to school? Sitters? Visitation? Third just because you file for divorce doesn't mean you have to move out of your home. You can live there until a judge tells you to move out. I figure since you said you had no money that you have no job so that is futher why they wouldn't make you leave. However that doesn't mean you shouldn't be actively looking. Also you can go to a Legal Documents Assistance, check your local phone book, they will have a nominal fee but you can apply for a fee waiver from the courthouse. And if they determine he could afford it they will charge him for the divorce. You can request allomony, I know I spelled that wrong, since you were not working through the marriage. People think only rich people have to pay that but every little bit will help as you rebuild. But it will only last for a while so again actively looking.
Not that I am a supporter of breaking up families or marriages. Make sure it is something you really want. A decision built on wants and needs instead of hurt feelings. The law does protect you from living on the street through your divorce though. Go to your local legal aid and they may be able to assist you with future details and good luck!