My question involves paternity law for the State of: indiana

Hello all.. I am going to probably be far too detailed but I figure its better than not being detailed enough.
in 2001 I married we'll call him Guy 1.. in early 2007 we separated for good after several split ups because he got abusive and I basically had a way out while he was in jail, at which point I went on to have a relationship with Guy 2 (not abusive thank you!).
Shortly after my relationship with guy 2, three months to be exact we got the shock that we were pregnant. At this time I had my divorce papers filled out, took them in to find out I could not file while pregnant. As soon as we found we were pregnant, not wanting more kids we decided on placing the baby with his step mother due to the fact that she could not have kids herself and greatly deserved them vrs. a stranger.
Fast forward 9months.. filling out birth certificate in the hospital I am told the only name I can put on there was legal husband, guy 1. Well I refused to do that and so never finished the forms before we left the hospital.
This was in late june 2008. In april I used our tax return to file the divorve, guy 1 and I were on speaking terms and he was seeing his children and does not deny he is not the father of the baby at all. He drug his feet on getting the papers from the post office and just today I finally got my divorce decree. I had to put the baby in the divorce as being his which I hated doing but because she was considered a child of the marriage... of course I find out today I could have put something in the decree disestablishing his paternity as well but its too late for that now.

As of today I still do not have a birth certificate for the baby, she has been in guy 2's Step mothers custody since day 2 of life and we would really like to get the adoption done and not have to worry about it anymore.
Guy 1 is willing to sign anything saying she is not his and guy 2 is marrying me and willing to sign anything saying she IS his. We'd love to be able to do this at a notary and be done without a DNA test so we can proceed with the adoption paperwork but are unsure if this is possible.
So I suppose the question is can paternity be disestablished and re-established with a notarized paper or is DNA proof needed??
Or should we just give up on that, file for a birth certificate and do the adoption as him being the father when he is really not and if so would that be fraud??
Thanks soo soo much for any help