I have found that the trick with sticky situations is confronting others early in the game, long before meltdown is even a possibility. And certainly people who confront via email should have their fingers rapped with a sharp metal ruler!
Debra Fine, in her book, The Big Talk, recommends the following openings to difficult-but-hugely-important conversations. These suggestions are far better than what I absolutely abhor hearing, that "I need to talk to you!"
There is something I'd like to talk with you about that I expect will improve our work together.
I'd like to discuss ________ with you, but first I'd like to hear your thoughts.
Do you have some time to talk? I need your help with what just transpired
I'd like to discuss the _____. We may have different ideas on how best to ________.
I'd like to come to an agreement about ________. I really want to hear your feelings about this and share my perspective as well.
Remember, successfully dealing with conflict, like everything else, requires practice.