There are several reasons why married couples end up divorcing. Some of those reasons are:
(1) The distrust between them. The triggers including dishonesty. If they don't trust each other, it will be very difficult to put them back together. This sharp but true reason is of course mostly left unsaid. What is usually disclosed to cover up this reason is a lack of communication or a lost sense of love.
(2) differences in belief, understanding, thought, religion, or the like between them. These differences are very difficult to put them back together. This common reason is also mostly left unsaid. What is usually disclosed to cover up this reason is the lack of communication.
(3) heartache or revenge; difficult to extinguish between them. The triggers may be domestic violance, unfulfilled promises, and misconduct by one of them. This sharp but true reason is of course mostly left unsaid. What is usually disclosed to cover up this reason is a lack of communication or a lost sense of love.
(4) economic (household) needs that are not met by the husband, and wife does not accept this situation.
(5) the marry under conditions of status that are not justified so that their marital status is invalid. For example, a man marries a woman who is still married to another man in another city or country; a man marries a woman who turns out to be his own biological sister (they live separatly from each other because they were adopted by different adoptive parents and live far apart); blood marriage (for the shake of maintaining property); polyandry; and so on.
(6) one of the husband or wife has made a very important decision (eg. selling their house, taking/spending a lot of partner's money/property, or adopting a child) without first seeking the consent of the other.
(7) the course of their household tends towards destruction (bad), especially if both have hurt each other (at least with words), and they are aware of it but have not found a way out.
(8) They (or one of them) are tired of their obligations and unable to continue their obligations as husband (for example, no longer able to support his wife) or wife (for example, no longer able to serve her husband at home/bed).
(9) Infidelity (one or both) is one of the causes of divorce. Some people can forgive a spouse who cheated on him/her, while others can't (get a divorce soon). Ironically, partner's non-jealousy in cases of severe infidelity (forgiving) is inappropriate; not normal & not good. People who are not jealous of their legal partner are less likely to take good care of their family (especially his/her daughter). Even so, if forgiven, of course this fact will be deeply recorded so that it will leave grudges (along with its various implementations) if the behaviour does not improve. Therefore, if their behaviour is not going to improve, divorce may be the best way for them.
(10) A wife's pregnancy that is not caused by her husband. This can be caused by several things, including: (a) severe infidelity, (b) fertilization of the wife by the sperm of another man (the husband is infertile but wants to have children in the family), (c) the wife becomes a surrogate mother, and the like. Of course, this condition is dangerous; can cause anger to the husband who can come at any time and cause unclear heredity and representation of the child. In this condition of pregnancy like this, to avoid bigger problems in the future, the husband should divorce his wife.
(11) Pressure or coercion from a third party (usually a parent or son/daughter from one of the parties) can also be one of the causes of cases of divorce between husband and wife, regarless of the reasons for these third parties. This reason is actually not really strong as long as the couple in question does not have a motive to divorce. However, in some cases, this general reason may be expressed by one of the parties (husband or wife) who really wants a divorce.
(12) Living apart for a long time without attention, news, and support (marital status becomes unclear or hanging) can also be one of the reasons for divorce. In this situation, in fact, the couple in question can maintain their marital status, although it is not clear. But in cases where one of the couple (especially the wife) wants to marry the other (obviously and officially), then this couple needs to get a divorce first.
(13) One of the spouses has violated (gross) religious rules (which have been agreed upon), violated the agreed (oral or written) prenuptialagreement (for example not having affair or/and drinking alcohol), or has committed and act that is very disturbing or disliked (hated) by the partner (eg. consuming drugs, alcohol, etc..). Of course, the real reason for this is rarely revealed. To cover this reason, some people say the lack of communication or the level of love that doesn't exist anymore.
Discussion:
Some people say that the communication gap (miss comm or lack of communication) between husband and wife (for example due to differences in wealth, education, insight, and association) is also one of the causes, factors, or reasons for divorce. Nonetheles, this seems odd, weird, or biased. Because, in general, communication gap (regardless of the cause) occur at the beginning of the meeting. If this was declared to be a big problem, then they would take this issue with it on the spot and they wouldn't get married. When a marriage occurs, it means that they think there is no communication gap between them. Then, after living together for a while, normally, the communication would get better; more tolerant between them. Therefore, it is strange if the communication gap is used as a reason for divorce. Of course, I still have a good opinion that the communication gap could be used as an excuse, but it means that this communication gap is a "result". So, the real reason, in this case, was not disclosed. Anyway, they want to divorce immediately in the name of "communication gap" or "miss communication"; misleading reason, but seem more elegant and common.
Similar to the above, some people say that one of the reasons for divorce is that their love (for their partner) has disappeared (lack of love); family life without love. This reason is of course a bit strange, it seems not the real reason; although it might happen. This reason is often used by some people (husband or wife) who want to divorce immerdiately because he/she has started loving someone else.They want to divorce in the name of "the lack of love". Misleading reason, but it seems more elegant.
Reflecting on the points above, there are several reasons for couples to divorce. Some of these reasons are highly interrelated; some of them may form a causal-loop.