Many marriages do have gender roles in order to help each other out. Though it is common that men provide and the woman cook, for example, it certainly does not (and should not) have to be that way. Especially in this generation, gender roles aren't as common as you think. There are a fair amount of stay home dads, where the woman is the provider. As long as one person doesn't feel like they're being taken advantage of, gender roles are meant to help the other out because marriage itself takes work and love. Generally, grounds should be equal with effort from both sides for a healthier relationship. But it varies per marriage, so basically whatever floats that couples' boat that works best for them as a team.