"There are three sides to every story: yours, mine, and the truth."
What it means is everyone has a point of view. A lot of times, even if they are an honest person, their viewpoint is colored by their own biases and perception. So the idea is that Oleg's viewpoint may not be 100% everything that happened, Maria's viewpoint may not be 100% everything, nor Trankov's. The truth maybe a bit in between.
Its a great reminder in general, why its not a good idea to take sides in a lot of cases when you don't have too, and even a reminder if your in a fight with someone that you may not fully understand things from their viewpoint or perspective.
I mean sure there are times when yes the truth is clear and there. But a lot of times when are talking about human beings and long standing relationships....
In general, I don't see why I need to make any of the parties the bad guy. The working relationship didn't work. All probably made mistakes. In the case though of Maxim/Maria. I think they would have eventually ended up on the world podium etc.