factor is the obligatory roles placed on wives and what they come to understand as their "duty". For example, "Vietnamese women are expected to sacrifice for their families, especially for their children, which includes, for some, acceding to husbands’ sexual demands". Their "duty" is to maintain family harmony and happiness. In Guatemala, violence within marriage is so normalized that wives come to believe that this is 'the way things are' and it is simply their role as a wife to endure the violence. This "normalization of violence [...] rests on a continuum of coercive power that makes possible the mistreatment of women not only in their homes but also in the community, neighborhood, and society at large". Further, because many of these women believe giving sex is their duty, they do not characterize their experience as marital rape. However, "women who have experienced forced sex in marriage understand this experience as an abuse or violation", they just may not characterize it as marital rape. Violence is so entrenched in many cultures it simply becomes a way of life, and wives are left to believe they must learn to endure it. On the other hand, husbands are influenced by the expectations of their masculinity. In Africa, these expectations include being a husband, father, and head of the household which requires men to provide food, shelter and protection. Along with this "obligation of being the provider comes the privilege and authority of patriarchy". As a result, it is often the man's perception that his wife has challenged his authority that leads to the violence. In the United States, masculinity is understood as a fixed entity that exists despite the changes of everyday life. It is understood as being in comparison to femininity, and more specifically, in opposition to femininity: Masculinity is to superiority as femininity is to subservience. Therefore, masculinity is correlated with aggression in such a way that scholars argue violence is a way for men to show their masculine identity. Another expectation of masculinity is that men are not to show their emotion. Instead, as Robert Connell argues, the "masculine prototype" is a strong and stoic man who appears to remain in control of the situation and his emotions. This sense of control in Western masculinity has direct implications for domestic violence. Scholars argue that some men use violence to regain this sense of control when it is lost. However,