Q: I rented iTunes movie on 16/8/15 and watch it in full on 17/8/15. When my husband tried to watch it 3 days later it had disappeared. iTunes States can watch movie as many times as you like within the 30 day rental period. Where Is my movie?

You conflated the terms of the agreement. A search of "movie rental" on apple.com revealed iTunes Store: Movie rental usage rights in the United States - Apple Support as the first hit. The page includes the following:

• You have 30 days to begin watching the movie after the download completes.
• Once you've started to watch the rental, you have 24 hours to finish watching the movie

HI, I rented a movie, it downloaded, but now I can't find it?  Shouldn't it say "play"?  Where do I find my rental?  If enter the name of the movie, it asks me again to either buy it or rent it - I don't want to pay again.

Where did you rent it ? If on an iOS device it should show in its Videos app for playing ; if a computer's iTunes it should show in the My Movies section of your library (possibly under a Rentals tab in it)

Thank you!  I didn't realize I had the video app.......