My DH didn't understand a thing about AP when DS was born, so I've been relating research & info I've found along the way. Almost every day I share an interesting fact with him (usually something I learned here!) He isn't the type to sit & read a parenting book or look at websites, so this is the best mode for me to share information with him. If your DH is into reading, get him some books... if he's into socializing, hook him up with a local AP dads group if you can find one... if he's a techie, send him websites & videos to check out... basically, figure out the best way to reach him & share the information you've found. I also think it would help if you sit down immediately & discuss which things are most important to you. For ex., I was clear with DH right off the bat that I didn't want DS left to cry, nor fed from a bottle, so I gave him the 'all clear' to drop baby in my lap whenever he was hungry or inconsolably fussy (your DH could possibly be trying to HELP you by giving your baby formula). I also said I NEEDED him to be in charge of diapers... that I was taking care of 100% of feeding DS, so I needed him to pitch in & change 100% of the diapers (when he's home, of course). But there were other things I tried to be more flexible on -- if DH wanted to put DS in a bouncer for 10 minutes, or push him in the stroller, or didn't want DS to nap on him, that was his choice (though it was sometimes hard to bite my tongue!) DS slept in our bed from birth but he stayed on my side of the bed & I only woke DH in the night if I really needed his help. Sleep was important to DH (not that it wasn't important to me too, but I was able to function at some level either way, and he wasn't). So you need to figure out what things are most important to each of you, and make it not just about "following AP" but about meeting your needs, DH's needs, and baby's needs... I don't feel like I'm being very clear here with what I mean, hopefully it makes some sense...
Anyway... fast forward, my DS is 23mos now and DH has been wearing him in the Moby (and is excited to try the Ergo I got for Christmas!) He is much more responsive to DS's needs & they have a wonderful bond. Some things still need work... DH is much slower about giving him something to eat upon request, so DS will come running to me instead... or DH won't notice he pooped (not sure how he doesn't SMELL it....) but overall he is awesome & tries so, so hard. DS now snuggles up to him for part of the night, it's so cute. For DH, he really needed 1) education -- about normal baby things, needs, AP, etc.; 2) space -- to figure out his own way of parenting; 3) time -- to adjust to fatherhood, to bond, to see what an amazing person DS is becoming. It helped a ton to be clear with DH about MY needs -- i.e. "I can't relax & enjoying reading this book if I know DS is crying & sad," so then he'd make extra effort to keep DS content so I could enjoy a few minutes to myself. Or, "I get painfully engorged if DS doesn't eat when he's hungry," so he would make sure to give him to me to nurse him.... things like that -- because at this point, it may be easier for your DH to meet YOUR needs (since that's hopefully something he's already been doing) than to calm this baby he hardly knows or, even harder, to conform to some 'principle' he doesn't understand, you know?