Is it normal to have replaced 3 fuel pumps in 3 years?

If replacing the electric pump only with a very cheap pump (China) yes. Replace the entire sender unit not just the pump with a well made unit and unless you have short issues you problem should be solved. May need a new wire harness to the pump which can be disconnected and replaced, it just replaces the harness running under the carriage underside and to pump assy. Also check your grounds to frame (Also near fuel tank) and look for bare wires to suggest a shorting issue.

Do you tend to run the truck out of gas or really low a lot? This is not good for fuel pumps.

Do some googling on the subject. New pumps can be damaged by faulty wiring and Dodge has had lots of issues with that. Also do not buy an O'reillys Master Pro fuel pump as they seldom last a year. This is according to my local O'reillys manager. He refuses to sell those.