Why do men say that they want children but clearly they don't?

Well, before the baby actually is there, most people have a very strong tendency to only see the good parts of being a parent, and they very seldom think of the more demanding and challenging parts. Then reality hits them...

Not sure why you are generalizing about 'men' based on one experience with one man.

For many parents, mother OR father, the reality of having a baby is different from the anticipation. Instead of a sleeping angel and lots of Kodak Moments, there is a lot of hard work and sleep deprivation.

But if he's really angry and unwilling to do his share or show affection, marriage counseling might be helpful.

He's (most likely) saying that out of frustration. A new baby is hard on any relationship. Once you all adjust and get into a routine, things should hopefully settle down.

that first year is rough, and no one can really mentally prepare you for what's coming. he probably doesn't think she's a mistake; he's just having a very hard time adjusting.

though i know it's tempting to be angry at him for what he said and you're feeling stressed too, try to take a step back. give him the space he needs to be honest about how hard this is. he'll be able to adapt better if he feels safe to admit to you and himself that having a child isn't what he thought it was. (chances are that it's not 100% what you thought it would be either.) after he gets his distress out of his system, he'll be able to work with you to do what you need to do to "grow up".

after i had my first child, i felt a lot like your husband. i thought i had made the biggest mistake in my life. i talked to a lot of other new moms and they felt the same way. we all joked that it's a good thing that there's no return policy or no one would make it past the first year. BUT, i grew up and changed and got used to being a mom, and now i wouldn't give my kids away for anything.

so be patient with each other. take turns getting time away when you need it. and, keep the lines of communication open and the keep the criticism of each other to a minimum. it's you two against the kid, lol, and she's got you two surrounded. you need to work together.