Our first "failure" was in 2002. We stopped looking for nearly 5 years, it was so bad. Then we started looking again, and found someone in July of 2008. We went through an on-again/off-again period through the end of the year, then she had some family/crazy issues and we backed off. As of April 2009, she was pretty much out of the picture, but kept coming back into the picture every month or so -- even though she was with another guy by then. (And this other guy is a really bad apple.)
In August, she started things back up with us--telling us that she was putting her relationship with him on a back burner. Bottom line, we discovered that she was actively seeing him and lying to us about it. When Ben confronted her, she confessed to the duplicity and lies, then tried to patch it back up. Ben let her back in, but within two days, she was already lying to us again and Ben ended it.
That was about 3 weeks ago. Ben is still torn up about it--yet relieved at the same time.
Again, the issue for us is the lying and the duplicity--although her choice in another partner really showcased her lack of character (the guy is a real sleaze-bag).
Didn't mean to take over your thread, but wanted you to know that we really do feel your pain.