It becomes very complex, but yes the difficult part is getting the spousal visa without a CENOMAR. Honestly, it would be sensible to get married whilst your still married in the Philippines. The Philippines doesn't recognise an overseas divorce either. I personally wouldn't have married someone who was still married in the Philippines, even if I could, because it would leave you wide open.
I know the annullment is a long process, but its worth it. My wife got an annullment, and it was a hell of an ordeal, but everything is legal and easy now.