There are many reasons why a couple may consider a divorce and while there are literally hundreds of reasons some of the reasons tend to stand out more, and are amongst the most common cited.  This may or may not be your reasons for a divorce but they are definitely worth noting.  

Poor communication
This is the single biggest reason that couples end up in divorce court.  Bad news is if you could not talk during your marriage to resolve issues, it is not likely to improve when you add lawyers and courts to the mix.  Expect a divorce based around this problem to drag out a while.  If you both had great communication skills together, you would probably be able to resolve your issues.  However, many couples have this problem and it is amazing each year how many more divorces are filed this year because of it. 
 
Financial problems
This is the second most serious marital problem that can occur.  Reason being that if you have financial problems, the rest of your life is full of stress.  If you are stressed out, the smallest things will irritate you and possibly create a huge fight.  This is never a good sign, try to do whatever you can to resolve those financial problems if you want to avoid divorce.  This includes curbing your shopaholic ways, saving more money, trimming back on bills, maybe even getting a better paying job.  But it is important to realize that not everyone has the ability to get a better job or cut back again on bills.  If this is not an option then you cannot totally blame your spouse.

Commitment problems
This reason can range from the I’m not prepared to really settle down after all, to the oh my god I just caught my spouse cheating on me version.  Which end of the scale you land on can vary, but there are actually times where a spouse is actually committed but just makes a foolish mistake.  However, if there have been several foolish mistakes then you know trouble is brewing in paradise.  Additionally, if your spouse seems to have problems adjusting to the married life then there may be commitment problems.

Change in Priorities
This can be minor but is usually a major change.  For example, when you meet you agreed that you always wanted a family as big as the Baker clan in Cheaper by the Dozen but after you get married suddenly, someone realizes that a house full of 12 kids is not the ideal household situation unless you are really wealthy and someone plans on staying home full time.  This can cause the other spouse to be highly upset and disappointed.  In addition, this same change of priorities could lead to a spouse being more concerned about succeeding at work rather than in your marriage.  The options are almost unlimited.  

Cheating
Many spouses do not care if it was a one-time slip up, or the fifth slip up they will not tolerate cheating.  This is another popular reason why spouses end up in dueling divorce battles.  

Unmet needs and failed expectations
If you marry someone with the assumption that they will help support you both mentally, emotionally and financially only to find them either unable or unwilling then you are often left with no other recourse than to seek a divorce.  

Alcohol, Drug, Internet, or some other addiction
This is becoming a huge biggie for a lot of people.  Nobody wants to be married to someone who has an addiction.  Especially drug or alcohol addiction because of the physical dangers involved.  

Abuse
Nobody deserves to be abused for any reason and his is a great reason to file for a divorce.  Never stay in a relationship that is abusive for any reason.  If you wish, you can always work with your spouse to help change things, but put a time limit on this.  If after a specific period of time things are not better then it is a good idea to call it quits.  

Stepfamily malfunctions
Let’s face it we all think that if we have been married before that the second time will be better.  However, if you have kids then it definitely is no guarantee.  How your children and your new spouse interact can often have a determination on whether your new marriage will be successful.  Additionally if you have an ex, who is determined to make life miserable your new spouse does not have to tolerate this situation.  Many second divorces occur because of this reason.

Parenting differences
Many times if you have children, you will notice that you and your spouse parent very differently.  While most families are able to resolve these problems, there are other families that are not able to handle this problem quite so well.  How this is resolved really depends upon how flexible the two parents can be.  However, if you are unable to parent effectively together while you are married, do not expect this to suddenly improve after a divorce.  It will usually get much worse.