Did she say the word pretending? Or is that how it came across to you? Because what I think might be happening is that she's saying in an inartful way that she doesn't believe you really want to cut your son out of your life, or any of the things you've shared on pc in recent weeks, but that she thinks your pain is driving you to see these drastic measures as the only option. If that's what she's trying to communicate, she's probably using triggering words or language with you that make you feel disbelieved or discounted.

When a person gets triggered, they stop hearing what's being said in the moment and get thrown back into the past--which, from what you've shared, is judgmental and abusive towards anything you say or do.

The difficulty is in having the pain of the past acknowledged—because it's causing you to push your son away—and not having it mixed up with the present, which I'm guessing you want to have a better outcome? If you don't want the present to have a better outcome, then that's where your therapist also needs to hear you. I really don't think she's dismissing you or your reality, but you're right in saying that it would help if you could share more of your internal life with her.