There are numerous possible reason which may give rise to divorce
* Suffering from diseases (especially disease such as TB, AID's)
* Clash of egos - inferiority complex (especially in cases when women earn more than men)
* Disapprovement or fights.
* Irresponsible partner.
* Mental Torture (especially by husbands / wife and inlaws)
* Physical Torture (especially by husbands and inlaws)
* No time for love
* No sexual enjoyment
* Unfaithful partners
* No Child - problem in having a baby (fertility problems)
* Financial problems
* Unrealistic expectations after marriage
* Bad habits - drinking, smoking, playing gamble etc
* Having affair with other woman or already having a second or third wife or have made illegal marriage. Viceversa (in case of women having affair with men) This is also called Infidelity
* Affair - if husband or wife find outs that the the partner was in a affair before marriage (Althought this is very very rare)
* Mad - if one of the partner is not mentally sound
* Dowry demands
* Misunderstanding or lack of trust (partner doubts that his/her partner is having affair. This may be also possible if someone ignites misunderstanding [may be a relative or friend] Beware!!)
* No emotional attachment
I guess its most important to have a emotional attachment after marriage - then only the marriage will be successful - otherwise it isn't. Misunderstanding is also one of the reason.