1. It keeps my sex life exciting
Let's be honest, having more than one keeps the variety and sexual experiences exciting. I couldn't imagine only having one partner at a time.
2. Why just settle for 1?
Unless you're married, why do you have to only have one? Be safe, know who you are with, and set boundaries. Then go enjoy!
3. More sex = more fun!
Honestly, the more you have it, the better you get, and you won't be able to go without!