Lovers who were generous, unselfish, very giving and always look out for the sexual needs of their partners enjoyed a much better sex life, revealed research published in the journal Social Psychological and Personality Science. Researchers studied 'sexual communal strength' - the willingness to meet a partner's sexual needs - in long-term couples. Both parties filled out daily sex surveys for three weeks. Four months later, generous lovers reported higher levels of daily arousal and more desire for their partner than the less-generous couples.