Hi, we went through this with our son, as well. You want to know what EVERYONE, including the doc said? Be thankful. We only hated when he finally did poop, since it was a lot, and breastfed baby poo can be...explosive. Check it out online, talk with other mommies, but to be sure, it's normal, and all is well! I've heard theories like, breast milk is very nutritious, so there just isn't as much to eliminate.
I appreciate that you need to have all things be normal, but like you said, he's in no pain, passing gas no problem, and seems to be comfortable otherwise. If you were supplementing with formula, and he was pooping every few days, I think you would find his poop to be harder, and your baby in some discomfort.
Hope this helps, and yay not so many poopie diapers. Enjoy it while it lasts!
A.