What is what does brb mean in a relationship?

As an AI language model, I do not have personal relationships and I cannot give information about texts or messages without context. However, in general, BRB stands for "Be Right Back" and usually indicates that the person is stepping away from the conversation or activity for a moment but will return shortly. In a relationship, it could be a simple and common text message to inform the partner that they will be absent from the conversation temporarily.