She has certain fears of sex, and a lot of inhibitions. There are distinct boundaries that never get crossed. I don't blame her, but she blames herself. Early adjustment problems are not at all unusual.
Most couples have questions related to their physical intimacy.
Since sexual development is such a private experience, there can be many reasons for the difficulty. It might be helpful to see a qualified counselor to help your wife work through feelings that block her orgasmic response. These can be related to early restrictive teaching that presented sex as dirty. Many women were never given the message that marital sex is a God-given gift meant for our pleasure. Another common cause is a woman's need for her own emotional control and her related feelings of anxiety as erotic stimulation increases.