3. Taryn, 28

My current boyfriend had just gotten out of an eight year relationship (married for four years) and we started out just having sex. This ‘casual relationship’ went on for about a year — with unofficial break ups in between. At the year mark of our hooking up, he told me he loved me and we’ve been together since (three years now — though on and off and rocky).

I was very surprised when the relationship changed because I started to become distant and gave up, even sleeping with another guy I was interested in. I had wanted to be with my current boyfriend a few months into our hooking up. I desired a more serious relationship because I really, really liked him and the sex was really, really good. He was very challenging to me and I liked that at the time (although he chased after me, he’s just a difficult person). It’s just a connection that the stupid heart wants — not the head. We’ve been together for three years.

4. Pilar, 27

All of my committed relationships started out as casual sex. It seems to be a cultural norm in my social circle; most of my friends’ relationships start out casually rather than as serious dating. This isn’t to say that the majority of the people with whom we have casual sex evolve into committed relationships; rather, it generally doesn’t happen. However, I have been in situations where my casual sex partner wanted the relationship to become serious, and I did not. Unfortunately, this, at times, has resulted in different levels of physical and psychological violence. The main thing that has catapulted my casual sex relationships into committed relationships is shared experience with someone who was truly my friend and with whom I had great sex. Generally, something has to happen that shakes the foundation of the fundamental relationship. If I get through an emotionally challenging situation and my casual sex partner stays by side and supports me throughout it, the relationship generally evolves into something more meaningful. On the other hand, if my casual sex partners steer clear in my time of need, it can remain as a casual sexual relationship. The longest casual sex partnership that turned into a serious relationship was three years. Then 10 months. A couple two-month relationships. Currently getting more serious with a casual sex partner.

5. Mattie, 18

We were best friends, hooked up with each other on and off for about six months, then developed feelings. Initially, we didn’t want a more serious relationship because we wanted to preserve our friendship. But the desire became stronger, and we decided to commit. Our relationship has become serious pretty quickly but is also very steady. We have been together for eight months.

6. Tom, 25

We slept together three times, then she asked if we could be serious so I said OK. We were together for just over a year.