Generally, people think of divorce as something that happens when couples just can't get along anymore. That isn't necessarily the case. There are specific life events that can lead up to a divorce. Knowing what those events are might help some people to realize what actually caused their divorce while helping others to avoid divorce.
Job changes are an aspect of a relationship that can lead to divorce. The main factor in this seems to be the employment of the man. Unemployed men are more likely to leave and women are more likely to leave an unemployed man. That isn't to say that is the only employment-related factor that can lead to divorce. Anything that shifts schedules or finances can lead to divorce.
Living apart, such as in military marriages, can lead to divorce. The toll on the marriage is increased over time, so a temporary change in living arrangements isn't the same as a long-term change.
Trauma, childbirth and illnesses are also likely to lead to divorce. The reason for these three events leading up to a divorce is fairly simple. One party might not be able to work through the event while there are ties to the event. That can mean leaving the marriage. Of course, all of these events can also strengthen a marriage. Childbirth, for example, is regarded as a happy event if both parties want the child.
Infidelity is a fairly obvious reason. It is possible for some couples to work through an affair, but other couples can't put that behind them. When they can't put it behind them, they usually choose to end the marriage.
A common reason for divorce among older people is that the children have left home. Some couples might realize that the children were the only thing keeping them focused on each other.
Source: Fox News, "7 life events that can lead to divorce," Amanda Macmillan, March. 26, 2015