Explaining what happened is fine. Explaining until they stop being upset is just excusing.

Context is useful once, as information. Repeated, it turns into an argument that the other person should not feel what they feel, and that is where explaining becomes pressure. You can tell which you are doing by what you are hoping for, since being understood and having their reaction end are not the same goal. The second one is about your comfort rather than theirs.

Say your piece once, then stop and let it sit. If you notice yourself finding fresh angles on the same defence, take that as the signal to go quiet. Ask what would help instead.