In fact, as far as I know, the size of the scrotum has little to do with sexual performance or even fertility. Bottom line: bigger balls (more testosterone) mean more promiscuity. Humans tend to fall in the middle of the spectrum when it comes to ball size. Some men’s contribution to fatherhood is little more than one teaspoon of sperm, while others are carpool-driving, baseball-coaching, baby-wearing dads.
They'll also probably be down to do that wild and adventurous sex thing you've always wanted to try, but never had the chance to (no, not 69ing).
They're the type to require a certain level of intimacy first, but once that intimacy is established, they'll be ~crazy~ in bed. You're not just going to be able to half-ass your way through every single conversation about their bad days at work. Don't worry, they're not secretly planning your future wedding.
This is known as hierarchical poly, where a couple exists that may even appear monogamous but dates others.
Over the course of a primary relationship, the secondary partners are likely to change, as is the couple or individual’s relationship with them.
This is a person who's probably into personalized scavenger hunts and tracking down a rare first edition of a comic book you didn't even know you wanted. Dating a monogamist will be a slow, steady (and healthy) balance of personal and together time. Even though they've probably had fewer sex partners than you, you can expect them to be a total god(dess) in bed.