This will help you determine the appropriate strategy. Consider the outcome for your ally as well. Do not assume either party understands their respective business. Be careful with emotional reactions. Make certain your response is based on more than emotion.
Emotion can effect judgement.
Time heals wounds like nothing else. This is especially true if the issues are trivial or petty. Review various scenarios to see if there is a clear winner. Watch out when your weaknesses line up with your ally's weaknesses. This makes you and them vulnerable.