I notice that when I pick up women for sex, I end up going through the phases of dating and instead of having a fun fling or a friend with benefits situation -that I want-, the girls tend to believe that I want a full blown relationship. Then they end up heartbroken when I leave or when they realize I'm seeing other women too. I understand I should be doing something differently to make them feel that this is a physical relationship only, but I keep screwing up this part somehow. I really dislike causing pain like this. During or before the dating how should I signal to them what I intend? Do you guys just tell them outright? Doesn't that scare away even the ones that would otherwise be into it?

Thanks!