Apple changed switched verification method, now requiring a second device.

HOw do I switch so that my verification code for icloud on Mac is is sent to the same device (Mac). Apple suddenly changed my settings and verification process, by now requiring me to use a 2nd device. I do not want to use a second device. I need verification to require no additional devices! Why was this changed in the first place? Should I not be in control of my devices, and not apple?