When is the last time you and your wife communicated? I mean, communicated, not talked. Once, after your marriage, you knew what she is thinking. Do you know that, still now?
It's very personal, but do you cuddle her while you two on the bed? If not, think why you don't do it any more. Too much of space is bad for marriage. Feel possessive.
Is the son, about a year old? If so, have you recently told her "you look beautiful." If not, when you said that last? Girl's feel they have lost the ability to attract the baby's father. They feel insecure.
It appears to me, she wants attention from you. She draws it through the son, whom, she is sure, you love. She cribs about small things, as she feels, you are not interested enough to look in to her problem. Do you feel, she has a point there?