Hi Ed,
Welcome to the forum! I split your post off into a thread of its own for you.
SpeedBump will be along and will help you out with getting a pump stop valve or, constant pressure valve.
I've got a bit of an idea of how they work and they will basically run the pump without stopping while you are using water during irrigation. I'll defer to him as the expert to explain how they work and what they do.
You have good reason to be concerned as frequent starts can shorten the life of a pump motor. Every time a motor starts there is a huge inrush of current to start the motor. This is usually in the neighborhood of 150% of the full load amperage during the start. This will cause heat to build in the windings of the motor and each successive start will add more heat. Eventually the motor windings will burn out.
A motor that doesn't start often and runs longer will last longer, than a motor that starts often.