You have two basic problems in this situation, and they are your co-worker and your boss. They are both demonstrating behaviors that are self-serving, counterproductive, and demotivational for those around them.
Your co-worker should not be running to the boss every time he has a complaint about you or your work. In addition, unless your behavior is beyond outrageous, your boss should not even be taking these meetings until your co-worker has first come to you.
Since your co-worker and your boss are not inclined to come to you, then you should go to them. Tell your co-worker that if he has a problem with you, he should come directly to you. Tell him that this is what you will do if you have problems with him, and the current situation is a perfect example.
If he rejects your advice, then you should discuss the problem with your boss. Stay away from the topic of his friendship with your co-worker, and emphasize the difficulties that the present situation is causing. If the two of them continue to team up against you, then perhaps you should consider teaming up with someone at the next level of management.
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