Disc prolapse is surely becoming the disease of the young this days and the major concern associated with it is the sexual activity which is a major taboo, even for the doctors to talk about. As you said, you have taken adequate rest and exercises and probably medications too. You should stick to the exercise plan as it seems to be helping you. Strength of lower back is sometimes needed during sexual intercourse. If you follow you treatment, you will be pain free and able to live a happy married life. good wishes.