I'm pretty sure the camera is suppose to behave like this by default.
This is a screenshot of when I use one of my 16:9 monitors , This looks good, and doesn't feel odd.
This is what it looks like with my 21:9 monitor. Note how the characater is closer to the camera and touching the bottom of the screen. Because the FOV is larger now, when turning the camera it now feels twice as fast as the 16:9 screen. Thus leading to the movement feeling awkward.
Another way to fix it is to allow letterboxing to occur in your game so it targets a preferred aspect ratio. It's and easier short term solution.