Even if the  the strong nuclear force is the most powerful force over subatomic distances. The electrostatic force is almost always significant, and, in the case of beta decay (which also involves a transformation of a proton into a neutron), the weak nuclear force is also involved. But the basic answer is yes, you cannot two protons together (Helium 2 doesnt exist, at least in a stable form), you need neutrons to compensate and add more strong force to avoid the electrostatic repulsion. Even if the strong force is stronger, it acts over very short distances, that is why elctrostatic repulsion wins sometimes, specially on large nuclei whare the strong force of a proton on the core has little influence on a proton on the external shell, but the lectrostatic force, is still strong as it decays slowly with distance remember that the range of the strong force is limited to distances on the order of a few $10^{-15}$ meters)