This is the most bizarre and exclusive relationship on Earth. Male and female schistosomes (parasitic flatworms) meet as juveniles inside a human blood vessel. The male forms a specialized canal (the gynecophoral canal) and literally for the rest of their lives—up to 30 years. They mate continuously. There is no divorce, no separation. It is a gothic, unbreakable, and utterly exclusive bond.
In the animal kingdom, there is a distinction between (living and raising young together) and sexual exclusivity (mating only with each other). Even species famous for their loyalty, like albatrosses , occasionally engage in "extra-pair copulations". Natural "Romantic" Storylines
In modern romantic storylines, releasing doves at weddings is a promise of domestic fidelity. It is the hope that your marriage will be as stable and boring as a pigeon's—high praise in the world of animal exclusivity.
