They do for a very short duration (10^-9 s.) Nuclear fusion happens by protons binding via the strong force, then one beta-decays into a neutron before the ele

They do for a very short duration (10^-9 s.) Nuclear fusion happens by protons binding via the strong force, then one beta-decays into a neutron before the electromagnetic repulsion pushes them beyond the range of the strong force. The beta decay happens fast enough in 0.01% of proton-proton collisions.