Couples have open marriages for several reasons. Sometimes, one partner’s sexual appetite is far greater than the other’s. In other cases, couples want to explore their sexuality with other couples. In still other circumstances, one partner may fantasize about bisexual encounters, or want to have sex with multiple partners. These experiences may not be possible within the confines of the relationship. When satisfying those sexual appetites is seen as beneficial for both partners and the relationship as a whole, many couples decide to have open marriages. Then they agree to certain ground rules and usually start with a trial period to see if it will work for them.