Polyandry (two husbands) is a much more widespread phenomenon than we have been led to believe. Polyandry is practiced around the world and has been since the beginning of time. In the Indian Himalayas, it still takes place in some areas because polyandry results in less fragmentation of land and also helps to keep the population lower. In certain areas of Tibet, women marry two brothers, as do the Toda people of southern India, for the same reasons. This is called fraternal or adelphic polyandry.
The Masaai of Africa have been polyandrous, although this is less commonly practiced today. It was used to help offset high infant and warrior mortality.
Partible paternity, wherein a child is seen to have more than one father, is practiced in about 20 tribal societies, primarily in South American. In pre-contact Polynesia, high caste women practiced polyandry.
Modern Western women who openly have two men in their lives tend to get vilified, called selfish, and a whole lot of less nice words than that, but having had some experience with a similar dynamic, I have to agree that it makes me one happy wife and that contributes to the stability and happiness of my relationship to my legally married to husband.
Good for you!