That's my point. How are you ever going to be sure the person you're with isn't going to go with anyone else? Put them in a closet for 3 months and get them tested, then repeat it the next time you think they're spending too much time on their phone with someone at all hours of the night? There's no guarantees for anything, but last I checked 7 billion is a terrifyingly large number of people, so clearly few share Primemuscle's Cassandra Complex about hitting it like other mammals do.
"The Cassandra metaphor (variously labelled the Cassandra 'syndrome', 'complex', 'phenomenon', 'predicament', 'dilemma', or 'curse') occurs when valid warnings or concerns are dismissed or disbelieved."
More than 2 million cases of the three nationally reported STDs – chlamydia, gonorrhea, and syphilis – were reported in the United States in 2016, the highest number ever.
An estimated 38,500 Americans became newly infected with HIV in 2015. Not a huge number to be sure, but it is enough to make one pause before dipping your stick in an unknown entity.
Yes, you can ignore me all you want, attributing it to my having a Cassandra Complex. Although I don't much like you, I sincerely hope you aren't now or don't become an additional number in these stats.