When more than one man is married to one woman at the same time, the men are brother husbands; the men are usually bisexual and the woman is straight. There are also Sister-Wives; in this case, the women are bisexual and the man is straigt. You can have as many brother-husbans or sister-wives as you want.
Tom and Bryan are both married to Katie! Tom and Bryan are Brother-Husbands!