However, even before these considerations, other savvy people will worry about the placement of their guests. The British continue to attach an almost paramount importance to it. More often than not, they ensure that the placement accurately reflects the social hierarchy. The householder usually occupies the place of honor, with the highest-ranking female guest to his right. The hostess is seated at the other end of the table, with the highest class male diners to her right. The spouses or companions of the two main guests are seated to the left of their high. There is another fundamental rule that no high worthy of the name is allowed to forget: spouses and cohabitants, including homosexual couples, must not be neighbors at the table. In addition, for a perfect alternation we will arrange to invite the same number of men as women.
Source: Very British - Lifestyle and traditions of the British Isles