Check out this thread to read all about the types of glue to use:
Glue 101
But the short answer is this: Model cement melts plastic together. That works great when you can't see it, but for clear parts, it "crazes" the plastic, making it foggy. So what the glue did was actually damage the surface of the windshield.
How big is the bad part? You may be able to buff it out.
Edit: Also, are you married/have girlfriend?
(Yes, it's relevant! :right: )