That and as mentioned above, the distance factor can also work to your advantage in a couple of ways. Like vlud said above, maybe she wants a short term affair, basically friends with benefits, no hard commitment type situation. Can't complain there but you have to know your role and almost negotiate this verbally that you want the same thing to proceed..otherwise if your serious and shes not, its going to push her away.
Then on the back end, or the other side of things...if you were to be in some area short term, and let this be known, it'd probably arise some interest for some girls, knowing they could literally do whatever they want with no recourse with the knowing your only going to be around temporarily.
I won't get into deep details,but I had a dabbling like the OP one time, and I sort of was getting the wrong idea at first and pushed her away, but then corrected myself in time and changed my tone then things proceeded as you'd expect, but I sort of had to first meet her eye to eye,and as well talk on that same level.
I guess one way to put this into a simple perspective, its like a exhibition versus seasonal/playoff game. The exhibition is just a match up that regardless win, lose , or whatever it does have any real effects, does not go on your record...and should be handled just as that. Now getting serious comparing to a seasonal/playoff game, or a serious relationship, a lot more is riding on it, alot more feelings, pressure, alot more comes into play and win or lose it seems to make a difference, seems to put a notch on your "belt"of record.