In what reason of the unsuccessful unions?

In what reason of the unsuccessful unions?
Unsuccessful marriage sometimes happens not only. Marrying (or having married), one of spouses starts osoznvat that the union was a mistake. In what the reason of unsuccessful marriages according to psychologists is covered?
At each person during life own priorities, ambitions, the principles are formed. Finding the second half, the person a priori waits that the elect (-tsa) will divide his interests, vital values, to help with realization of significant desires. In an ideal marriage has to help two to achieve the planned objectives, realization of the most desired hopes. However, if one of partners suddenly realizes that his dream was not achieved, feeling of disappointment, increasing as the snowball, turns into feeling of irritability which spoils the available relations.
In most cases marriage can rescue a simple straight talk. And the unsatisfied party should weigh carefully everything and to consider, analyse as far as its vital principles coincide with the principles of the soulmate and to think what of these principles can renounce for the sake of preservation of the relations.
Anyway the fundamental principle of strong marriage is the choice of the second half on the soul, after all in life of everything it is possible to achieve, if nearby - the reliable friend.