People’s perspectives on marriage and family often provide a valuable look into their belief system and worldview. Christianity and its various traditions, including Lutheranism, have much to say about these two issues. Many people have wondered if Lutherans marry non-Lutherans.
Lutherans can marry non-Lutherans. The largest Lutheran denominations don’t forbid their members from marrying outside the tradition, but conservative pastors implore them to marry Christians. Conservative Lutheran pastors may not say it is sinful to marry a non-Lutheran, but some would question the wisdom of it.
How exactly do orthodox Lutherans view the institution of marriage, and are Lutherans allowed to get divorced? How does the Catholic Church fit into all of this? Find answers to these questions and more in the following paragraphs.
What is the Lutheran view of marriage?
Traditionally, Lutherans have viewed marriage in accordance with the views of Martin Luther, although their views on marriage have changed throughout the years. (Also see What Do Lutherans Believe About Divorce?)
Luther defined marriage as existing only between one man and one woman. Any sex outside of this union is, according to Luther, fornication. This would include both premarital and extramarital sex for heterosexuals, as well as sex between people of the same gender. 
The primary purpose of marriage, for Luther was the creation of a family. In fact, Luther saw marriage as a vocation, and the rearing of children formed the main source of discipleship for a husband and wife. Because it existed before the Fall, Luther did not view marriage as a sacrament.
Although his views did shift throughout the years, it appears that Luther believed that marriage largely belongs to the legislation of the civil government. For this reason, all people — believers and non-believers alike, can partake in it. At the same time, marriage for Christians holds special value, as it reflects Christ’s love for the church.  (Also see Do Lutherans Drink Alcohol?)
Does the ELCA support same-sex marriage? Yes. In recent years, modern Lutheran denominations have held divergent views concerning homosexuality. The Evangelical Lutheran Church in America, the “mainline” Lutheran denomination, has revised their definition of marriage to include homosexual unions.
At the same time, their official documents recognize that a range of opinions exist concerning this matter, and the actual practices of each local ELCA church varies. (Also see Can Lutherans Marry Non-Lutherans?)
Does the LCMS and the WELS support same-sex marriage? The acceptance of homosexuality as a valid sexual expression diverges from the views of the two other primary Lutheran denominations in the United States: the Lutheran Church Missouri Synod and the Wisconsin Evangelical Lutheran Synod. These two denominations still define marriage as only existing between a man and a woman. 
Is marriage just for procreation or something more? In all three of these denominations, many Lutherans have started viewing the purpose of marriage to not solely be the creation of the family. Instead, clergy and lay people have started to emphasize the importance of companionship, sexual enjoyment, and unconditional love. This mirrors larger trends that exist within Christianity as a whole. Luther wrote in his commentary on Genesis:
“Today after our nature has become corrupted by sin, woman is needed not only to secure increase but also for companionship and protection.”Luther on Genesis 2:19
Can Lutherans marry Catholics?
In general, Lutherans support one of their church members marrying Catholics or a person from another Christian denomination. They base this upon the teaching of both Luther and the Bible.
Luther, who viewed marriage as a civil institution, not only supported Christians marrying those of other Christian traditions, he also did not oppose them marrying those of other faiths.
He bases this upon the fact that the Bible assumes that Christians will be in martial relationships with unbelievers, while never explicitly condemning the practice—2 Corinthians 6:14, which many use to argue against such unions, is not talking particularly about marriage.
“Do not be unequally yoked with unbelievers. For what partnership has righteousness with lawlessness? Or what fellowship has light with darkness?”2 Corinthians 6:14 (ESV)
Because of this, local clergy are free to counsel and advise concerning this matter as they see fit. None of the major Lutheran denominations have explicit policies on the matter.
The Catholic Church, on the other hand, clearly outlines the parameters of marriage in this regard. Catholic canon law differentiates between a natural marriage and sacramental marriage. A natural marriage refers to a man and woman who commit themselves to each other for life.
A sacramental marriage refers to, among other things, a baptized man and a baptized woman who commit to each before God for life. A sacramental marriage does not require that either of them be Catholic.
However, if either person has been divorced, that divorce must be annulled by the Catholic church before they can be remarried. If a Lutheran meets these qualifications and others, then they may marry a Catholic in a sacramental marriage. Otherwise, they meant enter into a natural marriage.
Can Lutherans get divorced?
Although Lutherans do not consider marriage to be a sacrament, they still take it very seriously. Scripture gives numerous, serious warnings about divorce and how spouses should cherish and protect the marital state.
Nevertheless, the Bible does allow divorce in certain situations according to Lutheran teaching. The interpretation of verses like Matthew 5:32 leads to the differing views of the various major Lutheran denominations.
“But I say to you that whoever divorces his wife for any reason except sexual immorality causes her to commit adultery; and whoever marries a woman who is divorced commits adultery.”Matthew 5:32 (NKJV)
Despite this difference of opinion, all the major Lutheran denominations in the United States allow divorce on some level. In general, the ELCA is more permissive in its grounds for divorce, while the LCMS and the WELS tend to be more strict.
The Evangelical Lutheran Church of America on divorce
Specifically, the ELCA allows divorce when trust is so broken that it cannot be repaired. The church does not go into much detail on the specifics of this broken trust.
Couples should seek wisdom: As with all important theological matters, the ELCA recommends that a married couple or estranged partner consult their parish pastor in order to know the best and right thing to do.
Marriages need to be filled with grace: They also stress that in a fallen world, marriage, relationships, and sexuality are messy, and that grace and forgiveness should always inform a Christian’s actions and decisions. While a Christian should strive to make marriage last for life, the reality is that sin has distorted all relationships, marriage included.
WELS and LCMS on divorce
The WELS, on the other hand, only allows divorce in the case of unfaithfulness and malicious desertion (see Matthew 19:9 and 1 Corinthians 7:15). However, even these reasons lend themselves to different interpretations. Does malicious desertion only mean physical desertion or can it also mean financial or emotional desertion?
Because of this, the WELS also counsels the concerned parties to consult a pastor. The LCMS holds similar views concerning the grounds for divorce. 
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