I've broken five pedals while touring, though none of them caused me to turn back:

First time: 12 miles from New Smyrna Florida on New Years Day, the right pedal spindle snapped. I pedaled twelve miles with one pedal and then on January 2nd was at the bike shop right when it opened to buy a replacement pedal.

Second time: While cycling the Natchez Trace Parkway, my right pedal spindle snapped. I pedaled thirteen miles to Houston, MS with one pedal. It was Saturday afternoon and the Walmart didn't have compatible size pedals. However, the 9/16th threading was the same as a spark plug. So I bought an "extra long" spark plug and used it to cycle the next 120 miles until I came upon a bike shop with replacement in outskirts of Jackson, MS.

Third time: Cycling through Paris, TN on a Sunday afternoon, the threading of my right pedal worked loose and stripped threads of the right crank, eventually completely tearing free. So, I found a motel and then on Monday rented a van from local car dealership to drive myself and bicycle to Jackson, TN where I had cranks replaced.

Fourth time: Cycling through Russia in town of Хлевное, my left pedal seized up. Replaced it with a spare I had along.

Fifth time: Cycling through Thailand, my right pedal seized up. Replaced it with a spare I had along.

So I've had occasions to have pedals fail, but typically I'm fixing them along the way rather than turning around.