When a break-up occurs, you don't get a termination letter from the lady in HR. You don't get two warning e-mails from your supervisor. You don't even get an appraisal or a letter of recommendation. All you get is a fresh list of colourful names to add to your vocabulary... and maybe a healthy number of torn/burnt clothes. Depending on how skillful you are at negotiating terms. The customary "What can I do better to change your mind" is met with an equally sarcastic answer. Just allow. You took a wrong turn, and you're elbow-deep in a mud pit. You could as well start molding pots to pass the time.
As all of you know, breaking up is never easy. You and your breaking up partner have to be on the same page, or else this happens.
So, it's very important that you first get your (soon-to-be-ex) partner up to speed on developments. That way, at least they won't wonder where this is coming from. Also, this is for the guys. Never, ever, break-up with the girl/guy (what? things have changed) from your own home. Do it at his/her place, or some other neutral ground. Not only do you remove the chance of falling back in...you also save yourself money in form of unbroken furniture/utensils/electronics/pets... Yeah, we know how crazy people get when you suddenly take away 'their precious'. We need to tie the loose ends.
Should you need a wing-man to help facilitate the break-up safely, remember to be on the same page. The friend has to help maintain your side, not question your motives or jeopardize the mission. Friendly fire cannot be tolerated.
One last tip. If you successfully carry out the break-up, the ex-partner is likely to blow a fuse. It's not a good time to bring up 'look on the bright side' anecdotes. He/she might cry some more and totally mess up that new t-shirt you just got from their replacement. But if the now ex-partner still looks sane, run! No, idiot! Not in a straight line. Try running like you're fleeing from a swarm of bees. Oh, maybe you might find yourself actually fleeing from a swarm of bees, but you get the idea. And if you hear a faint metallic 'click'... don't freeze! Just keep running, making sure you duck behind cover as soon as you can. Angry people usually don't have good aim. Er, at least I hope not.