do you think i should file to protect son and i financially? its the only way in my state to protect me.
Yes, if that's the only way your jurisdiction allows for formal financial separations and agreements. Your husband has already proven that he does NOT have you and your son's best interests at heart right now, and has already sniffed around about the boy's college funds.
I am as pro-marriage as they come, but at some point you have to protect yourself and your son, and I think that's LONG overdue.