Every year in America there are about 11,000 cases of sudden death during sex. While most of this is attributed to heart attacks, it's actually more complicated than it seems.
Back in 1999, researchers looked through autopsy reports to single out the ones that mentioned heart attacks during sex. They found that out of 21,000 reports there were only 39 cases of sudden death from a heart attack during sex. In the majority of those cases, the subjects were reportedly having sex with a prostitute.
While it's easy to assume that all that sexing with prostitutes was especially taxing to the victim's heart, it's also likely that cases which involved those dying at home while in bed with their partner were underrepresented. There could probably three times as many deaths from sex with a partner as there are from sex with a prostitute!
With odds like that, we wouldn't be surprised if some folks just stopped having sex altogether, especially once they find out that their heart just really can't take it.