Don't have a lot to add to the other two posts, but I did want to say something on the topic of divorce. Is it permissible? Well, biblically speaking, it is under a couple circumstances - adultery and abandonment (domestic abuse probably falls under the latter). There really isn't any instruction regarding the concept of separation (living apart, perhaps temporarily, but not divorced), so I won't say much about it either.
What I would like to say is, avoid it! For all practical purposes, jettison the idea from your vocabulary. Most of us are not subjected to the situations above. "Irreconcileable differences" they call it. Baloney. All differences can be reconciled in a way that allows a selfless, biblical-loving relationship to continue and, in time, thrive. God is the God of reconciliation. He changes hearts. Even hard ones.
Just because we have legal permission to divorce, say they commit adultery, doesn't mean we have to cast them out. Consider Hosea's treatment of Gomer (Hosea chapter 3), symbolic of God's relationship to us (persistent adulterers in our relationship with him). God doesn't simply divorce us, even though he is incredibly, justifiably entitled to do so! No, he lovingly and long-sufferingly calls us back to himself. Provided your spouse is repentant and wants your forgiveness, I would advise giving it to them. Shoot, do everything you can to help them do so. If you were unfaithful, repent and seek forgiveness. Easier said than done for sure, but a temporary period of hardship is so worth the fruit of a thriving relationship later.
If they up and leave (abandonment), I'd say it may likely be worth a shot (or shots) at trying to persuade them to reconcile and come back.
Get counsel from multiple Godly people if these situations arise. I say Godly because if they don't seek the Lord's will for their lives, they have no business counseling you. And be wise about marriage, yours will be tested! Never a bad idea to seek counseling early on, even when things are "okay", to help each other cope with the changes and see that the other is committed to building a life together. Don't wait until things break down to begin construction. Fortify from the start. Every single day be going about strengthening your marriage.
Anyway, that's enough on that. Hate divorce. Love forgiveness and reconciliation.
I love you all!
Dad