In looking over my post again, I would say that even unfaithfulness wasn't necessarily grounds for divorce, but abuse always seemed like a no brainer.
This sentence says it all. You
might be justified in divorcing for marital unfaithfulness, but where would you draw the line? Jesus says that even if you look at someone lustfully you're committing adultery, so even after a day both partners have probably committed adultery. And if you move on to the physical sense of adultery, why not just forgive? That seems like a much better option.
And the abuse thing...I would probably talk to a trusted pastor. For physical abuse, yes, hands-down you should get out of there. For emotional abuse it's a little trickier, as it's hard for you to discern what is actually emotional abuse and what is just your own pride. Again, talking to a pastor would probably be a good bet before making any hasty decisions.
In either case, the Bible is clear on the subject that if anyone gets divorced, they must remain divorced or else be reconciled to their spouse.
I'm saying that as a believer you are no longer bound by the law. But that you should seek God's will in all things to determine what is beneficial. If you have done so, then who can condemn you? And if you are not condemned, then why are you afraid; why do you doubt?
This goes beyond the law. In 1Corinthians 9 it explains that, though we are not under the law, we are
still under Christ's law, and Christ said that if you get divorced, you must remain divorced or else be reconciled to your spouse. Otherwise, you become an adulterer.
Now there is a big difference between "committing adultery" and "being an adulterer". Committing adultery is a sin, and therefore is forgivable. Being an adulterer means that you are openly rebelling against God, refusing to repent. The Bible clearly says that there is no place in the kingdom of God for an adulterer.
Also, our marriages are a direct representation of our relationship with God, and they are made to be special relationships. That's why, though abolishing the Law, Jesus still takes the time to explain that marriage is an exception; you still have to follow the rules and keep it Holy and Sacred if you want to be part of the kingdom of God.