If it were me, I'd consult with a lawyer even if you don't have the lawyer do all the divorce paperwork.
There are too many ways for you to get screwed. He can be out running up debts, and they can be put on your shoulders until you're divorced. You have back child support to deal with as well as the possibility he'll be a @#$@# and try to contest custody all of a sudden. Cover your butt!
Question for lawyer: if you agree to the divorce filed in Maryland, will you be bound by Maryland's way of doing things, even if it would've been better for you to have it processed in your own state? If things get messy, can you afford to fly out to attend a hearing?
Do NOT trust the ex to give you good information. He may intentionally mislead you or he may simply not know. His lawyer is also not the best person to be advising you; this is a conflict of interest for him.
Some info to get you started:
Maryland Divorce Laws - Maryland State Divorce Laws Divorce in Maryland