Can you explain what 3 Nephi 12:31-32 means and why it is not part of the Church rules?
You have two questions. Let me address each of them in turn.
What does this passage mean?
What it means is that unless there has been a serious reason, such as sexual immorality, you’re really not supposed to get divorced. It is a sin to break the marital covenants. And to simply get a divorce because “I just don’t feel like it” is breaking a covenant. We don’t think of it in these terms very often. But that is the fact. We break a covenant. But if one is already involved in serious sins anyway, they’ve already broken covenants. So, filing for divorce may be justified on the side of the innocent party.
Why is divorce not cause for excommunication?
You may not have thought you were calling for excommunication, but you were. What else could it mean that it is against “Church rules”? So, why don’t we excommunicate people who have been divorced? Jesus was asked the same question about why Moses allowed for divorce. His answer was found in a very similar passage in the book of Matthew.
7 They say unto him, Why did Moses then command to give a writing of divorcement, and to put her away?
8 He saith unto them, Moses because of the hardness of your hearts suffered you to put away your wives: but from the beginning it was not so.
9 And I say unto you, Whosoever shall put away his wife, except it be for fornication, and shall marry another, committeth adultery: and whoso marrieth her which is put away doth commit adultery. Matt 19:7-9
Basically, the Lord is working with the imperfect people he has. There are so many who get divorced for light or transient causes where it is impossible to determine just how bad it was or who’s really at fault. Finger pointing can happen all the time. And outsiders don’t now what to think. Did one of them commit adultery? Was one of them abusive?
If we only allowed divorce for abuse, adultery, or addictions, then some people would get it into their heads to accuse their partner of abuse simply because they grew tired of marriage. Then we’d end up punishing the wrong person. Because of these unintended consequences, there are some evils we have to allow to prevent innocent people from false accusation.
I feel where you’re coming from. I wish we lived in a world where people were more dedicated to their marital covenants and had been trained since childhood to deal with interpersonal relationships better. But we don’t live in that world. And all things considered, we as mortals need to accept certain wrong things to exist to prevent other wrong things from happening. I wish it weren’t that way. But it is.