Soap molecule has two parts - one which is soluble in water is called hydrophilic and the other which is soluble in hydrocarbon is called hydrophobic. When soap is on the surface of water, its molecules arrange themselves in such a way that its ionic end is inside the water. In contrast, the hydrocarbon tail is outside the water. There is a special arrangement of these molecules inside water, due to which its hydrocarbon end is protudes out of water. This happens due to the formation of a large clusters of molecules in which the hydrophobic tail is on the inner side, while its ionic end is on the surface. Such arrangement are called called micelles. Ethanol is a non-polar solvent. Therefore, it also does not have attracts to the hydrophilic part, hence micelles are not form when soap is dissolved in ethanol.