I don't know if having difficulty talking about abuse history really has much to do with not feeling a strong attachment to a therapist. I've always been really comfortable with my therapists, but it still took a LONG time to work through my abuse history. It eked out little snippets at a time over many, many years, and my therapists were okay with that. They said pretty much the same thing your therapist is saying, that for me it was probably safer to do that work small tolerable bits at a time so that the work wasn't retraumatizing. It made for slow work, but in the end it was very successful work. Have patience with yourself. I know at times it can feel like we aren't making progress, but we are.