 Citing studies suggesting that male same-sex couples have a relatively weak commitment to sexual fidelity and are relatively unconcerned about their partner having sex outside of the relationship, Gallagher argues that same-sex marriage would dilute the commitment to fidelity among heterosexual couples, thereby undermining an essential marital norm. And, with the fidelity norm seriously weakened, heterosexual marriages would become more unstable and the interests of children would be harmed.