Once i started 'seriously' dating my future wife, who i met on the job, i left and found another job. She left and found another job shortly after too. The worst part about dating co-workers is that your relationship becomes water cooler gossip;
If you guys aren't talking one day everybody gossiping "Oooh they're not talking today, wonder what's up?..etc,etc,etc.
Relationships are stressful enough as it is. The last thing i needed was sharing it with a bunch of ppl i worked with..ppl who for the most part, i didn't really care to be around....