Answer:
Here is a link to a page that talks about some of the errors and omissions found in the NIV and why: http://www.ecclesia.org/truth/vaticanus.html.
It all boils down to suing two “trusted manuscripts” that really shouldn’t have been trusted over some of the original Greek transcripts of the New Testament.
My Greek Bible has this verse in tact!
Thanks for the great question, and as you can see this is only one of the verses the NIV leaves out.