Being tandem riders and having pedaled over 230,000 miles on tandem bicycles since 1975 we have had only one bad experience with a fork.
It was steel (Reynolds custom 531) and broke/failed at 13,000 miles.
Together we tip the scales at 238 lbs so we are right in your weight category.
Currently have 34,000 miles on carbon fiber (Alpha Q) fork on our full carbon fiber tandem.
Have also broken 2 steel tandem frames. One break at 50,000 miles and the other at 56,000 miles.
Have ridden steel alloys, aluminum, titanium, carbon fiber and bamboo bicycles.
Amy material will eventually fagtigue/fail/break.