To be denied the opportunity to marry is to be locked out of one of life’s main identity-defining rituals. Marriage is both an expressive and legal act but for many same-sex couples around the world, it is not an option. Should our legal definition of marriage be expanded to include same-sex couples?
Gay marriage should be illegalShow moreShow less
Acknowledging any form of civil union between homosexual partners would condone an unacceptable practice.
Gay people are more likely to explore extramarital affairs than heterosexual couples. Therefore, allowing them to marry would undermine the fidelity of marriage.
In a recent survey, more than 79% of heterosexual men and women and lesbians in civil unions said they strongly valued sexual fidelity. Just 50% of gay men said the same. This illustrates the disregard for sexual fidelity among the gay community. 
Sexual fidelity is a widely accepted and celebrated norm of marriage. To allow homosexual couples to marry or enter a legally recognised union would be at best a disregard to marital fidelity, and at worst an endorsement of infidelity.
We allow serial cheaters to get a marriage license and marry a new partner. The government’s role is not to uphold the fidelity of marriage.
Additionally, this argument does not rule out allowing gay people to enter civil partnerships.
[P1] Fidelity is an essential component of marriage.
[P2] Gay people are more likely to have extra-marital affairs than heterosexual couples.
[P3] To allow gay people to enter the institution of marriage would undermine the fidelity of marriage.
[P4] Therefore, gay people should not be allowed to marry.
Rejecting the premises
[Rejecting P3] The government's role is not to protect the fidelity of marriage.
[Rejecting P4] Gay people can still enter civil unions or partnerships.