[MLBW]

By "hit" do you mean "spank"--or like hitting across the face or something? And if he is hitting him out of frustration--even spanking that's not a good idea anyway.

Is your husband a bit stressed out in general? Like is he nervous around the baby? (How old is your baby?) Is he stressed out at work? Children can often pick up on the stress of adults and it also affects their moods. How does your husband approach the child? Is he gentle, happy, loving--giving the baby a safe feeling? What is the environment like in your home? All of these can affect how the baby reacts to his father. If your son is a particularly sensitive, he may be picky about the people he wants to be held by--if he only sees his father for a brief time every day he may view him as a stranger--as he gets older he may outgrow this--however getting angry at him and taking out frustration physically will only reinforce that fear--it is the adult's (your husband) responsibility to be in control of his emotions and actions--a baby can't do that yet--they don't have the ability.