Why does my camera have the shutter open for longer when I have the LCD live view on?

Doesn't matter what I have the shutter speed set at - if I turn on the LCD live view, it is longer than if I don't have the view on. I rarely use the view for photographs but occasionally if I'm taking a picture at a very weird angle I need to. Nikon D5100

Do the pictures still come out right when this happens? If they are, then the shutter is NOT really staying open any longer. The feature that simulates the clicking sound may be affected, perhaps something to do with battery usage, but a good exposure is mostly based on aperture opening size and exposure length. If the shutter stayed open longer, your images would be over exposed, washed out, whiter.

It doesn't. The LCD screen just needs to turn off, I'm guessing. This just gives greater shutter lag, not a larger shutter speed.

The actual shutter speed remains the same.

To drive the live view system, your Nikon (and Canon works the same way) has to open the shutter so the image can get to the main sensor. When you press the shutter button, the camera has to close the shutter, clear the buffer, then actually open and close the shutter to take the photo. That is why you have a noticeable lag between shutter press and actually taking the shot.