She thinks that she is the best person to take care of the child and she wants everything to be done her way. As I have helped a lot till now with the baby's care, this hurts me. What shall I do?
I can't speculate with any certainty as to why your wife has decided that her opinions are the only ones that matter when it concerns your son's care. Many women do respond to their child's birth by assuming their role as mother gives them an inherent wisdom and final say about their child's upbringing. Clearly, both non-participatory fathers and those dads who want to share equally in childrearing, get the message quickly that their childcare opinions are not wanted or valued. Your wife may resent your "horning in" on her new "career," after all, you have your own career and this is something she wants to be the "authority" on.
Without blaming her for her past responses to you, I would calmly tell her that you don't want you and her to become more and more estranged over this and that you just want to be the best dad and husband you can be. Agree to talk at a time when you won't be interrupted. Each person should be allowed to express himself/herself uninterrupted to begin the dialogue. Tell your story, express your feelings (start all your sentences with the word I to avoid "blaming" sentences). Have her follow suit. Ask one another what you want and need from each other regarding parenting.
If your attempted dialogues always seem to break down and disintegrate into blaming arguments, you need professional help from a therapist who has handled these issues successfully. Interview therapists to get a feel for who would suit both your personalities. I hope you can both put your egos aside and tap into the love that produced this boy; then you'll be able to move more easily and joyfully into your new roles as parents.