Sratring problem bad relay

I've having trouble with my 93 Dakota. It first quit on me driving down the road, went dead as if I turned off the key. Then wouldn't start, would turn over but not start. Replaced the trigger in the distributor, replaced the fuel pump, and replaced the fuel pump relay in the underhood fuse panel. It then started and ran fine. Now it won't start again, primary suspect is the relay again. But why does it keep going bad, something must be causing it. Any suggestions anyone? Thankd for the help.