Fungus-growing termites live in an intriguing mutualistic symbiosis with Termitomyces fungi. The mutualism has often been described as a farming system in which the termite farmers cultivate their domesticated fungus for food. This cooperation between species evolved once, approximately 30 million years ago. Over time both the termites and their fungi have become mutually and obligately dependent on each other, even though in most cases the termites and fungi have retained independent reproduction and dispersal. Independent reproduction implies that the reproductive interests of the termites and their fungal symbionts are not completely aligned, leaving room for conflict between the partners. In my PhD I have studied this room for conflict and the possible resolutions. In addition to gaining understanding of termite-fungus symbiosis itself, gaining understanding of the stabilising mechanisms in mutualisms can increase understanding of the myriad of mutualisms that shape our world.