Hi Mushy, I was once like that with an ex bf. I left him because at one point I felt that everything was getting stale. I dated another guy after that (not that quick though) and after some time I just missed my ex. So I broke up with the new guy and went back to my ex. He was over me by then, so I got my heart broken.
That being said, it is possible, but please know that each case is different. There's no point following whatever trend or statistics.