The actor struggled in the searing desert heat during the three months he spent filming the gritty war drama, which scooped six Oscars on Sunday (07Mar10).
And Renner was so exhausted after daily shoots, he didn't have the energy to call his lover back home.
He recalls, "I was in a relationship at the time and, oh my goodness, it was torture. The time difference made it really hard. At the end of the day, all I wanted to do was go to bed, so I could have the energy to get up and do it all again the next morning.
"To sit down and try to sustain a relationship and talk about - I dunno - 'What did you do today? Oh, you went to the grocery store and you painted your toenails?' I mean, I don't care! I'm sorry, but I don't give a flying f**k! I'm trying to hold it together out here!"
The actor, who took his mum to the Oscars, is now single - and he is in no rush to find love again: "It's a good time to be single. I don't have time for anybody. The tragic side to all this is that it's a very selfish time, and it kind of has to be, and that's OK."