Basically, prior to man's departure from Eden, monogamy between a man and a woman was the ideal.
After man's departure from Eden, other sexual practices, such as polygamy and having concubines became a norm, though they were not ideal and lead to relationship problems such as jealousy (Sarah and Hagar) and favoritism (Rachael and Leah).
Regardless, the idea of love being between a man and a woman seems to transcend cultures and time periods, given that it existed as far back as when the story of Adam and Eve was written. How this ideal would apply to homosexual couples who are in a monogamous relationship, I'm unsure.