The centuries-old practise of Yoga has too many benefits to enumerate or pin point that do not affect one or another aspect of ourselves. It is a way of life not just qualified as asanas or pranayam etc so therefore yes, if practised regularly it can have a positive effect not only on your sex life but on overall health. The asanas help the body gain more flexibility and suppleness. The pranayam help regulate breathing so that also helps while performing sex. There are already 2 benefits of yoga for your overall performance. Hope it enhances your life!