The kingdom of heaven is like a merchant looking for fine pearls. When he found one of great value, he went away and sold everything he had and bought it. (Matthew 13:45–46).
The merchant in this parable shows us what our attitude towards our marriage should be. Husband, your wife is a pearl with a great value. You sought her earnestly and found her so she should be treasured very highly. Wife, just as the pearl being found will give great value to the finder, the same way you ought to give your husband great value for finding you.
Now that you have found each other, invest in your marriage because there are great returns for that investment. If you invest into your marriage and spend time, effort, and sacrifice in protecting your marriage from third parties, the chances for (eventually) having a rock solid marriage are quite high.
Marriage is designed to be an Exclusive Club, a two-person arrangement that provides a safe place for each spouse’s soul. There is no space for a third-party to receive an equal share in a marriage, because that can easily disrupt the safety and equilibrium of the relationship. The formula that ought to exist here is that of “forsaking all else” just like you recited in your wedding vow and nurturing each other because this union is too precious and highly valued by both husband and wife.