Being a slut is very much like taking the bus.

If you have ever taken a bus instead of walked or driven, you are and will be forever a Person Who Takes The Bus.
Traditionally defined, if you've ever had sex outside of wedlock, you're a Slut. Why do we focus on numbers so much to try and narrow down that definition?

It doesn't really matter whether you took the bus because your car broke down, your driver was off sick, you were tired of walking or simply fancied a change of scene, you Took The Bus.

Whether it happened just once and you will always treasure the memory, or it was a huge mistake and you will never take the bus again for as long as you live, or whether you are a regular commuter really makes no difference. You are a Person Who Takes the Bus.

If you have ever taken a bus, nobody asks you why and how often? They just accept that you took the bus and leave you to it. No explanation required.

If you have taken the bus and continue to do so, it is hardly something you need spend any portion of your life reflecting on. Some journeys may be more memorable than others, some drivers are gentler than others, some just want to get you there as fast as they can and some take their sweet old time.
Some of the faces on the bus will stick in your memory, you may have the odd conversation with fellow commuters or you may not, some may smell and some may be funny.
You might be brushing elbows, knees, kids or shopping, but you probably won't keep count of those brushes in your head.

Why is it different with sex?
By merging genitals with just one person you're not married to, you have become and forever will be A Slut. Own it!

By the way, this is hilarious:
http://jezebel.com/382609/is-sex-addict-memoirist-kerry-cohen-even-actually-a-slut