Team change - playing through life

I used to watch football games and be surprised at how easily the players switched teams.
Like for one championship, they would be fighting side by side, hugging each other whenever their team scored, and the next, they would be spitting at each other. Still fighting hard, but this time, against each other. It always puzzled me, how can they go from brothers to enemies in the blink of an eye?
And everybody said it's normal, the players understand it's all a game. Or rather, a business.
X has gone on to the opposite team because they would pay him more or offered better conditions. It's alright, though, it doesn't make him hate his ex-teammates, nor vice-versa. They're all still friends, at the end of the day.
And now, having grown up a bit, I find myself asking a similar question.
We were a team yesterday. Not all eleven of us, because this game is played on smaller teams. You and me. We were a team, a duo, it was us against everyone else.

We knew each other so well. I had nothing to fear from you, nor you from me. Every interaction outside this team was an oddity, an object of curiosity, to be discussed, weighed, even laughed at.
I used to tell you about the people I met, the thoughts I had, the jokes I'd heard. We had our intimacy, our collective of shared opinions and in-jokes. It was you and me, and only after that, there was the world.
Although we did not regard it with the same eyes, we were on two sides of the same coin. You looking out for me, me for you. We both knew what would affect one was bound to affect the other, so we were on the lookout.
And now, we face each other, on opposite teams. And suddenly, we don't know what to say. We're a bit like strangers, aren't we?
Yet how can we be strangers? When only yesterday, I would've cheered for your win, which was also my win. Now, it's not exactly my loss, I don't hate you for winning, but I don't cheer either, because this win suddenly means nothing to me.
Or maybe it does, maybe like a football player, I wish you well, because you were my friend. But my destiny is no longer tied to yours and I can only care from afar.
You ask. Your words imply a certain something between us. Your asking me about him implies there still is an 'us'.
And for a brief second, the old team is back, it never broke apart, it's still us against the world.
You're hinting at the intimacy there once was. You want me to confirm that I, too, am still on the old team. Of course there's no third party. No outsider.

But we're not on the same team, remember? Of course not, neither of us wants to, because then we'd also have to remember how it was. The old team, how we used to cheer for each other and how we'd take on the world together, which will invariably lead to the question - was it all a lie?
Me - guilty of leaving, you - guilty of staying. But neither wants to say it was a lie. Because it wasn't, although saying it out loud now, that's what it sounds like.
I wonder, as I look at you, waiting for a reply, if we could be like football players. It seems our teams have changed. Perhaps one didn't think the team was going where he wanted, perhaps he found a better deal somewhere else. Or perhaps, he was happy, but now finds himself facing his team-mate from the opposite side of the pitch.
At the end of the day, are we capable of good sportsmanship?