Bi-marriage

Now that same-sex marriage is legal in these United States, what about the rights of the bisexual? He or she is only allowed to marry one person at a time, thus restricting his or her expression of sexual orientation within marriage. Such a person may not believe in sex outside marriage, so that our laws prohibit the bisexual from a fulfilled sexual and romantic life. Is there not a case here for legalizing marriage to two people for this special case?