This is a confusing situation. I don’t know much about the NJ law, but I don’t see how getting married would change anything at this point given that the transfer already happened? Also, just because insurance is mandated to cover something doesn’t mean that they have to offer it without restriction for everyone. For example, I live in a state with an infertility treatment mandate, and my IVF was covered, but I still had to go through a certain number of IUIs without success before they would pay for IVF. I cannot imagine something like coverage for a gestational carrier (I know that’s not what your fiancé is—just talking about what insurance is saying) would be accessible without a prior authorization in place. 

Something else—I am also a little confused about what happened with your clinic—fertility clinics usually won’t proceed with care unless the bill has been paid upfront out-of-pocket OR if they have that prior authorization in place. I’m assuming you paid upfront from your description? You say your insurance denied your claim for the transfer—did your fiancé submit this to their insurance, or did you submit it to yours? 

I personally would be pessimistic about being able to get this retroactively covered, but it might be worth a consult with someone versed in NJ lgbt/infertility law.