The best that modern science can say for sexual abstinence is that it's harmless when practiced in moderation.
Sex makes you smell better. Er, in that it improves your sense of smell. And it reduces the risk of heart disease. And relieves pain. And even improves teeth. This Forbes article explains those and other health benefits of getting a little something-something.
Women are sexually aroused by women regardless of which gender they have sex with. "Researchers measured the psychological and physiological sexual arousal in homosexual and heterosexual men and women as they watched erotic films. There were three types of erotic films: those featuring only men, those featuring only women and those featuring male and female couples. As with previous research, the researchers found that men responded consistent with their sexual orientations. In contrast, both homosexual and heterosexual women showed a bisexual pattern of psychological as well as genital arousal. That is, heterosexual women were just as sexually aroused by watching female stimuli as by watching male stimuli, even though they prefer having sex with men rather than women."