I am no expert in this, my understanding is that the ideal in Orthodoxy is that a person marries once or remains a virgin (monastic or in the community). Second marriges are permitted in the case of the death of one person within the marriage, these however are not as joyful as the first marriage, divorce is also permitted by holy todition but is not encouraged and trodtion indicates that the people should then remain unmarried or be reconciled, although this may be relacsed by the decision of the bishop on a case by case bases. one of the key passages in this is Matthew 19: 2-12.
A number of the Fathers of the church speek on this isue reiterating what Christ himself says on this matter and St Innocent is clear that marrige after a divorce is not permited unless one of the origanal couple has died, he indicates in the text i have (which is an extract of his writings) that the penance for this which the church of this time considered adultery was savear. other writes from around this time indicate that devorce is only permited for adultery, even a differnce in faith is not an reason for devorce.
as far as i understand it Marage is veiwed as a once event which is ment to last for eternity even if death separates the couple for a time. this is not always insisted on as humans are only capable of living this way by the grace of God, as only his grace can allow us to live in this way as we were created to before the fall.
I am shore one of the more experence members of the forum will corect me if i have miss understood anything (i am still lurning)