When we first started RVing we had the same thoughts, buy walkie talkies....
They lasted about 2 trips and we decided they weren't worth the trouble. We now have developed a system of hand signals and wording for her to tell me what to do. She stands in view of my mirror and within ear shot. Usually tells me which way the back of the trailer needs to go by pointing. As long as the terms used are understood by both of you it prevents her from telling ME where to go
We developed this system after trying to back the RV into a tight spot after dark in the rain and we both got testy. When we realized we were yelling at each other we started laughing and decided to never again be one of 'those' couples you always see at parks
Now the walkie talkies are a novelty for the grandkids to play with.
Hope you find a system that works for you... but above all... patience!!
Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD 4dr short bed Duramax w/allison
Reese Fifth Airborne air ride king pin coupler with Sidewinder