Numbers chapter 5 brings up some issues that have already been addressed in previous books of scripture: atonement and adultery. Unlike some previous verses dealing with adultery, we now get a formula that the priest is supposed to follow if a husband suspects that his wife has been unfaithful. The wife really has no say in the matter, and let's face it, refusing to succumb to the priest's "faithfulness test" would probably be seen as an admission of guilt, the punishment for which is death by stoning. The formula assumes that there is nothing wrong with a husband being so jealous that he would make a spectacle of dragging his wife before a priest to have her tested. On top of that, as you can see, the "test" is really little more than witchcraft.
On the topic of atonement, this chapter of Numbers commands that any Israelite who has wronged another person should confess and make restitution. Some people today still expect that if someone has wronged them, that individual should take it upon themselves to apologize and seek to make amends, but that doesn't always happen. To make matters more complicated for modern-day Christians, the New Testament solution for these sorts of problems is for the "victim" to forgive. That's right, when someone has committed some hurtful act against you, Jesus doesn't say that they should offer a elaborate sacrifice. When you suspect your spouse of being unfaithful, Jesus doesn't say you should drag her before a priest so he can perform some hocus-pocus. His answer is, when people wrong you, forgive them.
This is one of those times when the simplest answer isn't necessarily the easiest answer, but there really is no reason to complicate things. If you have done something which has brought harm to another person, admit it and make whatever amends you are able. It's as simple as that. If someone else has brought harm to you, don't dwell on it, just forgive them and move on. There's no reason to be a doormat, but there's also no reason to bear a grudge. You can learn something from the situation and exercise more wisdom in the future, but once a deed is done, it's done. Forgive and put the matter to rest. People may not even realize that you think they've done something wrong, so stewing and waiting around for them to apologize is pointless. Even should you decide to inform people of their wrongdoing, they won't always respond the way you want. Forgive them, learn your lesson, and get on with your life.
Of course, if you have a relationship with more longevity, like what one would hope for in a marriage, it helps to cultivate open and honest communication. Forgiveness is still key, but it's also helpful to let the person with whom you're planning to spend the rest of your life know what you're thinking. That sort of meaningful communication requires vulnerability, not a power trip. It certainly doesn't require a priest to perform any special magical ceremonies. Simply communicate with the people you care about. If they don't accept what you reveal about yourself, it's better to know that truth than to live a lie. It's more likely that they have their own fears about being vulnerable, and they may even be grateful that you make vulnerability seem safe.
If you want to hold on to grudges and spend entire relationships protecting yourself, no one can stop you. Imagine for a moment what kind of life that would be. How satisfying and enjoyable is a life without vulnerability? How satisfying and enjoyable is a life spent demanding that other people apologize for what they've done to you? However counter-intuitive it may seem, meaningful relationships result from apologizing when you legitimately have something to apologize for, practicing forgiveness instead of holding grudges, and embracing vulnerable, honest communication in the relationships you value. That's not overtly Christian, it's just healthy human behavior.
It may be tempting to base decisions on how we think someone will react. In fact, we can probably come up with plenty of excuses for why we shouldn't own up to our misdeeds or forgive people who have somehow wronged us. Any excuse we come up with is ultimately going to boil down to one word: fear. The truth of the matter is that being honest and forgiving actually makes our own lives better. Fear saps us of energy. Grudges rob us of opportunities. Trying to hide from the truth about our own actions is exhausting. Being honest in our communication and forgiving people frees us to focus on the things that are actually important in life. Life doesn't have to be complicated.