Will my exhusband be ordered to pay child support?

I am currently going through a paternity/custody battle with my ex boyfriend. However, when i got pregnant i was separated from my ex husband. we were still married until april 2009 ( my son was born nov. 2009). when i went down to child support enforcement they told me that b/c i was still married when i conceived that my now ex husband is the legal father of my son. would he be ordered to pay back child support b/c of this technicality?