How can I get this case apart?!

If you're talking about the case-back,some 6119s open thru the glass..It states so clearly on the caseback..

If you already realised this and are asking how to get the glass off, either a crystal removing tool or pry gently around the edge of the crystal ring.

Anil

Forgot to mention... once you get the crystal off, you will see a little metal tab in the gap between the dial and the case around the stem area, this is the stem release. You may need to pull the stem out.

Anil

this case is listed in the casing guide, which will give more details about this type of case:

http://www.thewatchsite.com/index.php/topic,2218.0.html