Ursula’s Revenge by Allan Aldiss

A STORY OF LESBIAN DOMINATION - Emma, a young bi-sexual married woman, cannot escape from the influence of her dominant lover Ursula, an older rich lesbian, despite cruel abuse from Ursula and her big brutish Haitian 'butler' Sabhu, a former animal trainer. Ursula is furious when Emma twice has an abortion when pregnant due to Ursula's highly unusual forced breeding program and decides to auction her into actual slavery with a group of cruel Eastern Potentates.