A committed relationship by its very definition is a relationship where you are both bound to each other by an invisible but almost tangible cord. It is a relationship where you have made a pledge or promise to each other that you will be loyal to each other. And when we think of someone as loyal it evokes in us the knowledge that they are faithful to us and would never betray us by their behavior or in their speech. A loyal person treats you with kindness and affection; you can rely on them because they don't change on you; and they are on your side and will defend you against those who would attack you. So why is loyalty important in a committed relationship?
1. It cements your commitment to each other. When your heart is at rest in regard to your partner's loyalty since you are completely assured that they are faithful to you and are on your side then the invisible cord that binds you together in a committed relationship is strengthened. But when you are doubtful about your partner's loyalty then you cannot put all your emotions and energies into the relationship since the relationship is risky to you and so your commitment will be low.
2. It ensures you are able to face life together. When you know that your partner is loyal and they are on your side then you can confidently face life together. You can invest yourself, your resources and your talents and gifts on your partner and on your relationship because you know that you are both part of a strong team. You know your partner won't misuse you and what you invest in the relationship. If on the other hand your partner is unfaithful and you cannot trust them then you are more likely to each face life on your own as you cannot trust them to invest what you bring to the relationship for the betterment of both of you and your relationship. You are unsure that they will represent and take care of your interests as they are untrustworthy and your commitment to them will be weak at best and non-existent at worst.
3. You can both grow your gifts and talents within the relationship. When you know that your partner is loyal and devoted to you then you are able to focus your energies on growing as an individual and as a partnership. Because you are devoted to each other then your desire will be to see your partner happy and living at their full potential. And you will support them financially and emotionally in that. If on the other hand your partner is fickle and you are unsure about their loyalty then you will tend to either spend your time and energy on trying to fire fight the relationship fires that result or you will try and grow as an individual without any input from your partner; and your commitment to them will be as low as their commitment is to you.
4. You are able to support other people. When you know that your partner is loyal, dependable and is fully devoted to you only then you have enough energy to fend for others. And you can both take care of children. You have the support you need to raise healthy, well adjusted children. But when you cannot trust your partner since they are unreliable and their devotion is to themselves primarily then your energy tends to be dissipated within the relationship as you cope with this unstable and rocky commitment. If you have children they tend to suffer from this dysfunction.
The level of loyalty in a relationship is directly proportional to the commitment that you can have in any relationship. Minimal loyalty or loyalty that varies with circumstances tends to result in little commitment since you just cannot rely on each other. Complete loyalty that stays steady regardless of circumstances results in high relationship commitment as you can rely on each other.