There can be many reasons to break up, and they may vary from person to person. However, by paying attention to some of the reasons other people have broken up, you can better identify the warning signs that may appear in your relationship.
Are There Good Reasons to Break Up?
As the philosophers say, everything has a beginning, a middle, and an end. Relationships are no exception - even the most optimistic wedding usually includes "til death do us part." There may be reasons you need to break things off sooner than that though, and they tend to fall into one of three categories - trust, communication, or life.
A Lack of Trust
The obvious way that trust can be betrayed in a relationship is for one partner to cheat - that is, go outside the agreed-upon boundaries of the relationship. For some this is automatically a "dealbreaker," but others try hard to get through it, and it is possible to regain trust. The problem is that regaining trust has to be done by the one who has lost it, not the one who cheated. The betrayed has to find a way to forgive his/her partner - and stay forgiving. If the person says she has forgiven and then holds it against the cheater later, that's another breach of trust.
You can also lose trust in a relationship when your partner doesn't act in a consistent way, or in a way that you expect him to. It doesn't have to be an affair - it can be hanging out with friends while neglecting the relationship, or spending money without regard to consequences. Regardless of the situation, trust always has to be given, not earned - and if someone repeatedly betrays that trust, there may not be any left to give.
You Don't Understand Each Other
Even more essential than trust in a relationship is communication. The only way people can trust each other is if they are able to clearly communicate their needs, concerns, and positive thoughts without fear. When lines of communication break down, that's when a relationship becomes two solitary individuals who feel lonely and lost in what used to be comforting and happy roles, as part of each other's lives. One common way that communication breaks down is simply that the individuals talk with other people - perhaps their co-workers, their friends, or even their family. The problem is they talk with everyone except each other, and if they're unwilling to take the steps necessary to repair the communication, it is probably time to give up.
It Wasn't Meant to Be
As John Lennon said, "Life is what happens when you're making other plans." There can be all kinds of reasons why circumstances make either trust or communication or both impossible. Job relocation is one of the biggest reasons to break up, even if trust and communication are there. Other responsibilities can also cause people to drift apart - different schedules, for example, or a decision to go back to college.
There's also simply the fact that as time goes on, people grow and change, and they don't always grow together. Values can change for each person, and where they don't match they may become irritating to the point where the two people feel they have nothing in common.
You're Not in Love Anymore
Perhaps you're not in love anymore, or you were never in love in the first place. You'll know this when you start avoiding your partner or having arguments. Perhaps you simply want something different, feel strung along, or keep wondering if there is someone else better out there. Some couples will slowly stop talking or go on dates and not say a word to each other, while others have more dramatic fights.
You've Been Wronged or Cheated On
Being cheated on is a surefire sign that it's over. While some people do forgive and forget, being cheated on is a traumatic experience and it definitely signals it's over. Cheating is an especially hurtful way to end a relationship, as many people will cheat as an excuse to move on, rather than confronting the problems in the relationship and ending it first. Other things like acting jealous, being passive-aggressive, or being disrespectful are red flags.
How Will You Know?
There is a simple way to know when a relationship is over: it's when one of you is no longer willing to try and make it work. Any relationship takes two people to keep it going, but it is hard work, and there may come a time when you feel that there is no point in trying anymore. If your partner is the one who calls it quits, it may hurt even worse because you still want to keep trying. Whatever the case, being honest and nonjudgemental is the best way to bring your relationship to an end with dignity and without acrimony.
Remember that just because a relationship ends it is not necessarily a failure. You can almost always find ways in which you both benefitted from the relationship, and holding on to these memories can help turn bitterness into treasure.