WASHINGTON (AP) — For nearly six years, a senior Secret Service agent kept his extramarital affair with a Mexican woman a secret from the agency responsible for protecting the president. But in the wake of an embarrassing prostitution scandal involving 13 agents and officers, Rafael Prieto’s secret was revealed by a fellow employee amid concerns the Secret Service wasn’t enforcing its rules consistently. With an internal investigation ongoing, Prieto apparently committed suicide last week, people familiar with the matter told The Associated Press. Prieto, a married father assigned to the security detail for President Barack Obama, admitted the years-long relationship...