The next chapters presents characters and explains the world's idea in that everyone belongs to everyone. This, to me, means everyone has a right to you in the physical aspect. Therefore it's easy to see why the people of the BNW are regularly involved in sexual activity with many different people. Being promiscuous is seen as the right thing and staying with only one person is seen as outrageous.
Image from http://www.theoutsourcingcompany.com/blog
There is one person who stands different from the rest, Bernard. He feels that this idea of belonging to everyone is not quite right and so therefore likes to be alone most of the time. Though, Lenina, a popular girl, is very curious about him, and she finds his short height and personality to be endearing, also a little strange too (remember every person in BNW is engineer, even their height). I believe soon they will form a relationship and possibly travel to the Savage Reservation.
The more I read into this book the more I find it bazaar and fascinating. Also, I'm really glad I don't belong to anyone!
Thanks for your comments on my previous post.