On the clinical end, remember, YOU set the pace. Often we come into a scene where any number of people are rushing around like headless chickens -- and that can include Fire and Police and Doctors, too! That's where it's most important to establish yourself as in control.
Now "in control" is all about moving deliberately, as if you know exactly what you're doing. Often, coming in to the scene it takes a little while for you to figure out WHAT you're doing. Start by standing at the edge of the forest and looking into the scene rather than jumping in and begin bouncing off of trees.
It's most important that during those initial moments you relax your pace (without falling asleep), keep your mouth shut until you know what you're going to ask or say, identify who or what are the obstacles in your way and then, start building a plan from simplest and most expedient to complex.
As time goes on, you'll be doing stuff like this automatically so be gentle on yourself, you ARE on a learning curve.
As for the domestic situation, the only thing I see lacking is a safe environment for you and your wife to sit down together, talk about what's going on (alternating speaker and listener), making sure you really understand what the other's concerns are (there is always something one level deeper that produces the real "hot button"), and coming to agreements that you can each live with.
I think relationships live or die according to the clarity of the agreements made between people and the way they honor then.
On your part, start with agreeing to something small and structured. Then follow through. This begins to build trust, and I think, ultimately, that might be what you're missing.
As far as the relevance to EMS goes re: domestic issues, it's no different than learning a new way of communicating with a doctor, nurse or partner so you can better get the job done you're supposed to do. Being a medic means learning to be a better communicator, and the impact of the job is such that you have to learn to use those skills in every aspect of your life.
Blessings, and thanks for relying on this forum for support!