Not sure what issue you’re running in to. I control my Sonos system from multiple iPads, iPhones, and Macs. 

Random thought; the controller in use does have to be on the same WiFi and subnet that the Sonos is on. It can also be controlled from the new web interface remotely, if you provide authorization. 

If I access Sonos on my iPhone my wife cannot control Sonos from her phone or pad.

Why not??

Meaning if I play music using my iPhone and she tries to lower the the volume in the room she is in  
her iPhone or iPad cannot . We used to able before upgrades.

Not sure what is going on, I can do this from any device that can reach my Sonos system. Have you tried to call Sonos Support directly to discuss it?

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.