OK.
Well, you got me thinking about two things
1. male/female (philosophical)
2. key (technical)
Here are my thoughts on male/female... A female singing this would seem appropriate, but... would not a male singing this song be more meaningful? Would it not show male understanding and compassion (perhaps this is one reason your wife likes it)? It is an "issue" that seems to be prevalent today among feminists... male "ignorance" (which we are not).
As for key, when I was listening, I thought that if you sung in a lower key, you might release the same dynamics in your voice that was so expressively played on the guitar. It might also allow you to dance a little with the range as it will be more in your comfort zone.
What I found mostly about the vocal performance was you had no room to go up, and could not always go down (for musical reasons) which forced a "flattening" of the range. Does that makes sense?