I am in the military.

So my estranged husband and I were married 24 Oct 04, and have been separated since 1 Aug 06. I PCS-ed from RI to cali in Dec. When we separated in Aug, we wrote an agreement that stated I would give him $500 for support( I was living in the barracks but still recieving BAH). Itt was notarized but never filed legally. Now that I live in CA, I have an apartment. So I am recieving married BAH but living single. In Feb, I had a consultation with an attorney who deals with military. She explained to me that since the agreement was never legalized, RI has no juridiction over me, and the most I should be giving him is the difference between married and single BAH. Which is what I have been doing since Feb. And since then my estranged husband is constantly threatening to screw me over, and get me for all the money he can.
Currently I am preparing to file for divorcec(in CA there is a 6 mo residency rule before filing). The attorney I will be working with told me the same thing the previous attorney did. But he still tells me that he can get me to no only pay for him after we are divorced but pay backpay for when I started the lesser amount. The only way I know he would get money after divorce is if he could not support himself and if I retired. I have only been in for 4 1/2 years. And he has a job and an apartment, which means he is able to support himself. My attorney is out of town right now, so I am waiting til she gets back, but until then, Give me some advice.