Fuck Buddies

So, Fuck Buddies. Friend's who hook-up.
For this discussion we will consider "fuck" to cover not only sex.

I guess I just don't get it.
I have never been in anything besides a commited relationship.
I have never kissed outside of one, let alone anything that is near intercourse.

My boyfriends roommates on the other hand seem to be very big fans of this practice.

I've read articles before about how they are unlikely to work because someone will inevitably gain feelings for the other. From my stand point this seems pretty true.

For one of the roommates, who we will call Al, had this happen to him. He decided to engage in a "Fuck Buddy" relationship with a close friend of his groups. Apparently they had both decided at the beginning that this would be nothing more than simple sex (is that even possible?). Then I was told that Al had developed feelings for this girl and would not mind pursuing something more from her than just sex. She, though, had just gotten out of a relationship and had no interest in one anytime soon. Al then decided to keep up with the "Fuck Buddy" relationship and still is now.

But I can't help but wonder how long that can really last before someone gets hurt. He obviously has already developed some feelings for her and would you not assume that they will continue to grow? There has to be a point where he can't just settle for just sex with a girl he has feelings for.

And how do two people go from something so intimate to just a platonic relationship? You have seen that person naked, you have been as physically close to someone as is possible without being conjoined. How do you forget that and go back to before?

This all could just be the fact that I am most definitely "The Relationship Type." But really, I don't see how this could benefit anyone in the long run.

***I don't know how well this will go, it's my first attempt at more serious writing.***

I would love to hear your opinions/stories on the subject.