She squeaks when she blows her nose.  He eats like a rabid pig. 
It's just not working out.

We've all spent some time stuck in a relationship we didn't want to be in because we didn't have the heart (or some other equipment) to end it.  Maybe we don't want to hurt someone we've been close to, or worse, maybe it's clear right away we're dealing with a nut and we don't want to be the trigger for an economy-sized bottle of Prozac and a six-week stint at the Bendy Willow Psychiatric Center.

So what do you do when it's completely obvious you're just not meant to be together?  You break up.  Or, you try to break up, don't quite hit the mark, and end up sucked back into the awful relationship for round two, because you just couldn't make it stick. 

Is there a way to make it permanent without causing permanent damage?

The key is to have a plan, a good plan.

Location, Location, Location.
It's really important to pick a good strategic breakup setting. 
The best places to have "the talk" are both public but fairly private, with a convenient escape route.  The best location?  Outside, walking at a park.  It's crowded enough to ensure you won't have a big scene, but private enough your dumpee won't feel like he or she is naked at a funeral.  Other agreeable breakup locales include restaurants (but not a favorite restaurant) or a walk around the block.  The worst place to break up?  At a party or work.  The only thing worse than being dumped is being dumped in front of people you're going to have to see on a regular basis.

Timing Is Everything.
Another key to effective breakups is precise timing.  Breaking up at a park gives both your dumpee and you the chance to leave once the deed is done.  If you're ending the relationship at a restaurant, do it only after the check has come and you've paid for dinner.  (And by the way, if you're about to dump someone, you should DEFINITELY be buying dinner.)  There's nothing more horrifying than being dumped and then having to sit around making small talk for another 20 minutes while you're waiting for the check to come. (As in, "Hey Lula, what are you doing now that you don't have plans for tonight?  Laundry?")

Happy Freaking Birthday.
Never break up with someone within two weeks of a major holiday or his/her birthday.  Make that a month for Valentine's Day and Christmas.  There's no faster entry to the Bitch/Bastard Hall of Fame than permanently destroying the holidays for your soon-to-be-ex. It's just not nice, and you don't want that what-goes-around-comes-around thing biting you in the ass when your turn as the dumpee rolls back around.

It's Not You, It's Me.
The first thing to remember is not to drag it out.  The longer it takes, the worse it is for everybody involved.  Whenever you end the relationship, be sure to make your reasons relevant only to you.  Say, "This is not working for me." Stick with your basis and keep repeating yourself over and over if necessary. It's impossible for someone to argue with you about reasons that pertain only to you.  If you end up getting sucked into a situation where you have to list grounds for wanting it over, you may find yourself in for an encore.  If you say, "we fight too much" or "you don't seem happy" your partner may offer to change, taking all the air out of your break-up and landing you right back in the relationship.

Hire A Hit Man.
Worst-case scenario, you're too much of a weenie to breakup with your girl or guy yourself, you can always resort to the newest companion service to online dating.