Hi, and thanks for your medical question on eHealth forum!
Inability to enjoy sex is called frigidity. However you may not be frigid. What you probably mean is that you never had an orgasm. This could be achieved by proper stimulation of clitoris, G-spot in vagina, increase the foreplay, talk with your partner and discuss how you get stimulated, watch movies that stimulate you, create an environment around you that stimulates you. Sometimes the foreplay is not adequate for the female to be aroused as the arousal time of the two partners is different.
The other possibility is that you have vaginal dryness. There are many problems that cause vaginal dryness such as hypothyroidism, Sjogrenâs syndrome, vaginitis or inflammation of vagina, dermatitis of skin around vagina, condom allergy, or allergy to soaps and lotions.
Since a confirmed diagnosis cannot be given on net and without running some basic tests please discuss these possibilities with your gynecologist once. Hope this helps. Take care