This is kinda going in a different direction, but hey! - it's related.
Well, if we're bringing sexuality into it...
It seems to me (through years of blended information, no sources, I'm afraid) that there are two viable methods of reproduction. Though both methods work for both genders, I'll call the first method the "male" method because it caters to the short reproductive cycle which is characteristic of males. In the male method, bands of warriors wander and wage battle. The strongest / best men win in battle, and thus win the right to reproduce with the greatest number of / most desirable females. I'm no expert on actual Viking society, but my impression is that the men would pillage villages and rape all the women. This method ensures that the genes of the strongest warriors are passed on to a new generation of fighters. As barbaric as such a method sounds to us, the male method of reproduction is not mutually exclusive with civilization. A society which utilizes this method of reproduction is perfectly capable of composing beautiful music, authoring works of literature, and crafting other works of civilization.
The second method, on the other hand, caters to the long reproductive cycle which is characteristic of females. The female method involves a woman ensnaring a man to stick around for longer than it takes to simply conceive of a child. It's better for a female to conceive a child with a strong, genetically superior male than a weaker man, but it takes more than genes to raise a child. What a man may not be able to give in terms of a genetic predisposition towards strength, he can more than make up for by sticking around to protect the homestead against wayward barbarians, opening pickle jars, etc.
I can conceive of ways to compromise between these two strategies, but neither really sits well with my idea of what a healthy relationship should be. A society may develop a method of awarding wives to a man based on his accomplishments, with the caveat that he must be able to support each of them. Another may more closely emulate the female strategy, yet humor the man's tendencies by allowing him to hunt, fish, and guzzle beer on the weekends. The flaw with both the male and female strategies is that one gender is always enslaving the other, for the lone purpose of advancing one's genes. Such is nature - survival of the fittest, no? I think that many, many sexual fantasies deal with acting out one of the two strategies above.
As relationships go, however, I'm a fan of neither strategy. But a compromise won't do either. A relationship isn't about letting the more powerful partner have his/her way all the time, nor is it about cordoning off different areas of expertise in which one partner has a complete say and the other has none. It's not a battle for control, and it's not about dominance or submission. As I see it, a relationship involves the blending of two individuals to create something greater than either of them alone. Ideally, a relationship satisfies the emotional and physical intimacy needs of both partners, but it's also more than the utilitarian image conveyed by that statement.
Let me try an analogy. Everyone needs to eat. Suppose two people (initially complete strangers) eat lunch together every day. Over lunch they talk, and they come to confide their thoughts and feelings in each other. They each enjoy the food as well as the discussion, and come to create a bond of friendship. While their relationship was initially based on the idea of meeting needs for food, their friendship comes to transcend that. Their nourishment needs are met, but their relationship is so much more than just lunch. So it is with a romantic relationship, except that the buffet is the other person. =P The bond transcends the role of need-fulfillment. Two people come together to create something greater than the sum of its parts alone.
So, in conclusion, a lot of sexuality is tied to dominance and submission as a sort of legacy connection to past methods of reproduction, but a modern relationship is about balance, connection, and transcendence rather than dominance and submission.