redatlanta has it right. Consult a family lawyer NOW who can advise you on the best strategy for arranging things before any separation. Don't guess. I used to try to do all the research myself, and got myself tied up in knots because I'm just too close to the situation.
Incidentally, many lawyers will reduce their fees as a professional courtesy to lawyer clients. All the lawyers I have ever dealt with did that for me. Just ask before you sign a retainer agreement.