For me, a rupture is when the relationship is in jeopardy. It could be anything between a misunderstanding to a disagreement to an actual hurt. And I agree, usually trauma feelings get triggered. Hurt, pain, betrayal, and fear are usually feelings involved.

L explains it as a dance where each person involved has a role they played. It's not about blame, but about owning your part like you said.

It sounds like you're so used to the blame game that not only do you blame yourself, but also your therapist. Blame is not necessary. Empathy and curiosity and kindness are. Working through and learning from ruptures are important to growing in your relationship. And I do think apologies are important both verbally and in actions.