Will the Cable Splitter effect my internet?

Hey, Well Im going to try to hook up my computer to my HD TV, the main problem is, where the TV sits (I cant move it because there aren't any good places except where it is) there is only 1 cable outlet, my question is If I use a splitter so I can use both will it effect my internet, now I know people have said it will degrade a little but if im not using the Cable and the internet at the same time, will it still degrade quality? I.E. If im playing a game on my computer will the internet be slow even though im not watching TV, "Flip side" If I am watching TV but not playing a game will my Picture or sound quality be messed up, I am going to get a Dynex™ - 2-Way Coaxial Cable Splitter, please tell me if my Tv quality or my internet quality with be noticeably different (better or worse) thanks guys.