Keep watching more will come out but:

It was a constant arc over Season 2. Nate often felt put down. Even back in season 1 he was bullied by Issac and Colin to please Jamie. Ted knows what Jamie did to Nate but still invites Jamie back. Nate gets a bit addicted to the “Nate the great” line that Ted gives to boost him up but that sours when he brings back Jamie, then brings back Roy to help coach. Look at Nate’s face when Ted says “we need a big dog” to talk to Issac. He can’t get the window table at taste of Athens but the hostess says if Roy Kent wants it, they’ll reserve it for him. Nate also doesn’t see that Ted has the photo the two of them at his home. So in Nate’s worst-case-scenario mind he probably threw it out (Nate thinks way too far ahead often, look at when Ted and Beard asked Nate for his thoughts on the team in S1 and Nate went into what he thought would happen if the coaches hated his thoughts. Watch how he’s desperately trying to get some approval from his father with the “wonderkid” newspaper and he gets nothing. Watch how he scrolls through twitter for the highs of praise but how quickly he comes crashing down when he reads some comment of how he looks like a dork or whatever. Look at Jan at Rebecca’s dad’s funeral commenting on how childlike it is to have another man buy you a suit (the suit he loved because Ted got it out of respect for nate instantly became something he hated). Also note at Rebecca’s Dad’s Funeral… Rupert is whispering in his ear. Maybe Rupert’s been doing that for a while. Pay attention to what Rebecca says about how Rupert is going to get Zava early in S3.