It's pretty normal in high school to break up, makeup and then break up again. We know, we know -- it's just so hard to stay away from a hot ex! But we got news for ya, girls -- it's no different in Hollywood. These famous couples are so on-again-off-again that we can't even keep track! From Miley and Liam to Kourtney and Scott, check out the 10 couples that just can't call it quits -- but then do -- but then don't.