How to train in relationships?
Train in every situation and relationship with kindness and gentleness, and contemplate with wisdom the best response to suffering. Sometimes the best response is to only listen in loving silence and offer words of sympathy and understanding. Avoid the harmful attitudes of judgment and criticism of others and oneself because violence in any form is not helpful in uprooting the pervasive conditioning of ignorance, unwholesome habits and wrong views. Instead, train to be sensitive and understanding of the degree of wisdom, ignorance and state of the emotional body of the other and in oneself.
When the other is open to another perspective could we then share our insights. However, most people are not ready to consider a view different from their own. Therefore, in most situations, the best response is kindness and unconditional love. When the time is ripe and the other asks for advice and is clearly open to another viewpoint, can we explore the possibility and range of openness in the other, and then gently speak of the Dhamma in language that the other can understand.
All we can do is the best we can with what we know from experience. We all make mistakes and learn from the mistakes. Self judgment and blame is not helpful and is a defilement. Act gently and be not hard with others or with yourself. We are not perfect and are growing in understanding of the Dhamma.