matt had a therapy appointment today. I wasn't there because I work every saturday.
the therapist (who I have met once and matt has only met with 5 times including today) decided to see him alone, without any parent there.
I met her last week, and she did not mention her desire to do things this way. we were with his last therapist over a year (she left practice recently to go into teaching) and not once did she see him without a parent.
I am beyond pissed. I wasn't consented, and SO called me after the fact (while he was leaving to grab some pizza)
I want to be consented BEFORE changes are made to his care. I think I deserve that. I don't care if this is how she 'always' does it, I want my opinion heard and I want the opportunity to ask questions like what she hopes to accomplish.
SO thinks i'm disrespecting him and not trusting him. he says he didn't have time to tell her he had to 'call the real parent.'
i'm thinking why not just say 'maybe next time, we should both weigh in on this.' i'd sure as hell consent him before changing things without even seeing how he felt.

Could you clarify whether you are upset with SO for not checking with you or upset with the therapist for making the change without talking to you about it first? Or maybe both? You definitely deserve to know fully what's going on with your child's healthcare and consent fully to it. It sounds like you said the right thing to SO in terms of framing it not as you being the "real parent," as he put it, but in terms of the importance of you both discussing your child's healthcare in a co-parenting relationship.
I would say the first thing to do is weigh out in you head, outside of this incident, whether or not you are comfortable with M seeing a therapist without a parent in the room. If not, maybe find another therapist. If you would consider it, then maybe you could talk to M about what his experience was like and get his input? Or maybe you could work something out where you start out seeing her with a parent in the room until you get to know her/get comfortable with her. Also, who did you hear about this therapist from? Did your last therapist recommend her?
Anyhow, I'm sorry that it happened that way and I hope you figure everything out.
To me, it's a big red flag that you saw her last week, and she didn't mention this. If she was the one who said to you that she "always" does this to justify it, I'd leave the practice. To be honest, if Matt hasn't hit it off with this therapist, I'd consider leaving even if it was just your BD who said it. From the brief period of time you've known her, she did something you were majorly uncomfortable with. If Matt does develop a good relationship with her, changing the care will be extremely hard. So strongly think about whether you want to stay with this practice.
Also, is there ANY way that you could swing being the parent that took him to therapy? Changing your work schedule? Changing the time of his appointment?
This therapist was recommended by our other therapist. Because I work every saturday and my day off floats around, I can't swing being the person who always takes him. I could, at best, be the person who takes him sometimes.
At first, I was upset with my SO for not consulting me. He didn't feel the change was a big deal, Matt didn't seem apprehensive about it, and SO is very comfortable with her. I think my anger at him stems mostly from just not being used to someone else making decisions about Matt.
I talked to my sister about it for a while (without telling her that SO and I got into it about this) and she was appalled. Not because the decision was made by SO, but because the therapist never mentioned this at the last session or prepared us for it at all.
I can't switch therapists because I don't want to do that to Matt right now. If he's getting used to her and talking to her, he went through a really bad patch when his last therapist left and he's just bouncing back from it, so I guess I'm stuck right now.
what WAS discussed with her last week? What I am trying to ask is- last week, was she talking to you about the session and saying things like "and then the parent will be over here while M and I will be in this corner of the room"? It would be one thing if she lied to you if/when you asked her about M being accompanied during sessions, or if she offered that (false) information. And it would be another if you never asked and she never mentioned it, if the assumption (on her part, but not understood by you) was that he'd be working one on one with her. I mean, M is the one there for therapy, so he should seeing the therapist, whether a guardian is there or not- so long as you can reconcile with this and tease out whether that makes you uncomfortable, or if it's more like you said- that it is an adjustment to accepting your SO making decisions about M. Hopefully, this is an opportunity for growth in your relationship and for his relationship has a parent to M.
also, I want to say that if you trust the referral source, you may want to consider trusting the current therapist's treatment decisions. She must have reasons for deciding to work one on one, and you can feel free to ask her to tell you specifically why. I totally agree that you and SO need to come to an agreement on how to handle things in the future, while still making him feel like you value his involvement.
nothing was mentioned at all. she has all the notes from his previous therapist which should let her know I was always present and 1 on 1 was never discussed. I am very upset with her handling of the situation. I used to work in this field, and it's very unusual for a child under 12 to be seen without a parent and even then, it's always discussed beforehand. after everything's been ironed out now, I don't think it's a problem per se, but it should have at least been mentioned at one of the sessions. any of them, not just the one I was present for, and it was never mentioned once.
you are right, it should have been mentioned, and it seems negligent that it wasn't. I have to say that I do not think it is unusual for children to be seen alone, though it absolutely should be discussed beforehand. I would guess it depends on the presenting issue for why they are there to begin with. Some research literature on play therapy talks about the danger of the parent being there in circumstances when there is abuse in the home- but that is a more rare circumstance, there are other factors, too. Many children work better ("work" as a general term- could refer to anything behavior-related, really) without their parent present because it can be seen as a distraction, an "out" to have a parent there. one example is sophia's creative movement dance class- it is for 3, 4, and 5 year olds and takes place behind a closed door. the teacher's philosophy is that she has the child's attention much better this way than if a door is open and they can see their parent in the mirror and know they can run out of the room. they're not kept their against their will- a child got upset the first day and was brought out to the mom, but i hope you see what i mean. i also havea speech-language pathologist friend who works in an elementary school and she much prefers working without the parent (although she is not against it) because you get more accomplished that way. there is a much different dynamic when it's one on one, and i think it's a good thing. it's a safe space for them to work with an adult in a trusting, duty-free way- in my opinion. all this of course does not excuse the fact that you feel misled and your so made a decision without consulting you.