How to divide an object with Blender 2.8 i am trying to divide an object: 

in Edit Mode, i select "Loop Cut". But the selection is only possible in that way that it divides the object in half. I didn´t found a solution to change the selection. If i wont another selection, i have to repeat that step.

But that is ok, i can live with that. 

My question is, when i selected the region with the "Loop Cut", how can i process the cut? Found no possibility. The region where it would cut is shown but i can´t execute it. (I know, this is a rudimentary question...)
I am showing you on a cube.
If you are loop cutting from exact center, that is Ctrl + R and Right Clicking mouse button to exit sliding.
In Edit Mode:
Go to face select mode.

and select the faces on the other half.

Now press P and seperate by Selection.

Go to Object Mode(by pressing Tab)and select any half of cube and Press G to Grab and move.



  This same method works on Blender 2.79 too.


Now cube is divided into two different parts! Enjoy.