I will offer the alternate opinion.

I have invited a 3rd party into my therapy sessions. I wanted my T to talk with my bff because he has known me longer than anyone outside my FOO, helped me through some of my childhood trauma, and has a background in therapy. I felt T and I were stuck, she wasn’t able to understand what I meant when I said (or didn’t say) things. BFF has a way with words that I do not, he knows me like no other... it made sense to me that he could help T help me.

It really weirded out my T. It’s unorthodox, for sure. She worried that talking with someone about me without me would harm our relationship because I wouldn’t know what was said.

We compromised - I arranged one day for BFF (who lives on the other side of the country from me) to be available during my session. We called him on speakerphone on my cell phone (so T doesn’t have his contact info) and talked to him for around 15 minutes (mostly him talking to T, but she asked some questions). Afterward we spent the rest of the (55min) session talking about the phone call. In particular, T spent time talking about what she heard, understood and thinks based on what was said. I have to trust that she was honest with me, but it did give me the opportunity to give some corrections or explanations.

I could never do this with someone from my FOO. It was super scary and hard to do it with BFF and I’m more honest with him than I am with T! But. It was beneficial. I think because I could trust that T was not talking “behind my back” and I knew everything that was said, it actually strengthened our relationship. It made me feel like she was taking me seriously and that I’m important. Or something.

Perhaps some approach like that would be more favorable? I think the key is to make sure that *you* have the power. I fear that if your mother had access to your T (even hypothetically) it would fill you with fear and suspicion and tear you and T apart. If all the contact is in your control, with you present, you can talk about what you both heard and feel right away.

Another option might be to work with T to formulate a letter or email with questions for your mother and then you can send them and bring any response in to read with T.

I don’t understand how vehemently against this some folk are. Unusual doesn’t mean automatically that it’s bad. I would spend some time making sure it’s something *you* want to do (not just what T wants to do) and then figure out a way to keep the relationship safe and uncontaminated.