I commute anywhere from 50-70 miles a week on my fixed gear and I've had a very crucial part on my bike break twice this year: the handlebars. First time I had some cheap Origin-8 bullhorns and they broke right to the right of the stem. This opted me to spend the extra money to get a decent bar of handlebars so I bought some Nitto RB-002 for something like 70$. They broke on the exact same side in the same place as the Origin-8's. I had a pretty awkward one handed 2 mile ride to my parent's house for Thanksgiving dinner. I'm an average weight rider, 160lbs, and don't run that big of a ratio, 46/16. I had assumed that Nitto had a good reputation for quality so I'm assuming I'm doing something wrong here. I'm wondering if this is a common problem or if it's exclusive to me? Also, can you recommend a solid pair of handlebars that are going to last more than 5 months?

Here's a couple of pictures of the Nittos that just broke.