Dilemma: breaking a truce or losing the game?

This discussion applies for games with 3 or more parties.
I'd like to know the opinion of the community on this extreme case.
Situation: you have a deal in place with another player. You made the deal because it benefited you, but since then the game unraveled in such a way that you'll lose unless you break that deal.
Should you break it or lose it?
I understand the 2 main arguments we'll see is the Herm Edwards' "we play to win the game" (deals are made to help you and you should not follow them when they don't help you) and the "one single game is not worth a loss of reputation" (breaking an agreement and getting backstabber tags may compromise your future ability of deal making + keeping the deal and losing is the ultimate "trustworthiness" proof).
What is your opinion on that?
I'd like to know the opinion of the community on this extreme case.
Situation: you have a deal in place with another player. You made the deal because it benefited you, but since then the game unraveled in such a way that you'll lose unless you break that deal.
Should you break it or lose it?
I understand the 2 main arguments we'll see is the Herm Edwards' "we play to win the game" (deals are made to help you and you should not follow them when they don't help you) and the "one single game is not worth a loss of reputation" (breaking an agreement and getting backstabber tags may compromise your future ability of deal making + keeping the deal and losing is the ultimate "trustworthiness" proof).
What is your opinion on that?