Amber, congratulations on making such a great decision for your baby. I hope you have a fantastic labour. I think that Kelly is right in suggesting that you find a support person to help you achieve this goal. My little suggestion is that you get your midwife or ob to put a big note on the front of your chart with highlighter on it saying not to offer you drugs or an epi. Most midwives are really caring people and when they see you in pain thier first instinct is to try and reduce it by offering you drugs. If they don't offer them to you you don't have to worry about being tempted when the time comes IYKWIM.
Maybe you can help your DH by suggesting a bunch of natural ways he can help you with the pain ie massage, getting heat packs, breathing with you, getting you cool drinks. I think men hate feeling usless in the face of pain so if you can show him ways to help and be proactive he might cope better. A good support person will help to support your DH as well as you.

BTW I'm due in March too - on the 22nd. Why don't you pop into the march belly buddies and chat with us here. The more the merrier.