Yeah, when I was still single (and a virgin) I had a couple of "Christian" girlfriends dump me, saying exactly that.
One later repented and is living a reasonably good life although she's still single; the other continued in her Bible-defying ways and got into a very bad marriage that didn't last long and caused her rivers of tears.
It surely is not because they has pre-marital sex...
I speak from the point of being un-married, married and know problems exsist in marraiges has nothing to do with the fact they were sleeping together before they tied the knot...