I am not in the exact same situation either, as I am the one who changed her mind (said I wanted kids then decided I really didn't)...but I can empathize with what you and your husband are going through. It's really really painful and scary...like you thought you knew where things were going, generally speaking, then something big like this comes along and you just don't know which end is up anymore. I think the counseling is a good idea, I think it can't hurt to have a third party hear what is going on. I agree with indigo2--you two have been through a lot recently, and sometimes when you have one big change you think you want to change a bunch of other stuff too...but given some time, you return to familiar patterns.
No matter what happens you should NOT have a child if you don't want it. You are right that you will live in resentment--not only with your husband but also with an innocent person who didn't even ask to be here in the first place.
Of course, your husband may be just as adamant about having children, in which case, saying goodbye might be the only option. I'm facing that with my husband right now, and he says he doesn't want a divorce, but no one knows what he will feel in a few years.
I am dealing with this by crying a good deal when I can (my way of getting things out) and also trying to be very gentle with my husband, because he is hurting too. It's a very raw situation and being short with each other won't make it any better.
Listen to your husband, go to the counseling, and keep talking to each other as you try to sort this out. But most importantly, be true to yourself. Don't let anyone talk you into something you're not sure about.
I hope it works out for the two of you--please keep in touch!