I have been with my boyfriend for around two years now and have been sexually active with him, and him only, for about a year and a half. The sex is good and I get very stimulated but never have an orgasm. But we are all different in a lot of ways, and this is one of the differences. However, do not despair.
Many women have to learn how to become orgasmic and then it becomes easier and more reliable.
One mistake made by a lot of young couples is to assume that the woman's orgasm should occur with intercourse. This is the most difficult way for the vast majority of woman and, in fact, it is probably the majority of women will never reach orgasm with penile-vaginal stimulation. For most women, clitoral stimulation is essential and many women have discovered this through their own masturbation. Self-exploration and stimulation is recommended for women who have never experienced orgasm, for there is no pressure, when alone, of worrying what a partner is thinking. Finally, through self-pleasuring a woman takes ownership of her sexual body and her sexual expression.