My future MIL went behind my back to tell my fiancé I need therapy for “trauma” – how do I handle this?

I’m dealing with a really uncomfortable situation with my future MIL (67f) and need advice on how to proceed.

Some background:
My MIL and I (29f) had a close relationship that became strained after some family conflicts. During our recent communications about these issues, she mentioned that I have “trauma” and suggested I should see a therapist.
Instead of discussing this directly with me further, my MIL went behind my back and reached out to my fiancé (33m) She told him that I have trauma and asked him to encourage me to get therapy to deal with it.

I’m really upset about this for several reasons:
– She’s diagnosing me with “trauma” based on our relationship conflicts
– She went around me to talk to my fiancé about my supposed mental health issues
– She’s positioning herself as someone who knows what’s best for my psychological wellbeing
– This feels like a massive boundary violation and overreach

I feel like she’s trying to paint me as the problem that needs fixing, rather than acknowledging that we simply have relationship issues that both of us contributed to.

My fiancé told me about the conversation, but I’m not sure how to handle this situation. I’m angry that she went behind my back, and I feel like this is manipulative behavior.

TLDR: MIL decided I have “trauma” from our relationship conflicts, then went behind my back to tell my fiancé I need therapy instead of discussing it with me directly. Feeling like this is a major boundary violation.

How should I respond to this? Set boundaries? I’m worried this behavior will continue after we’re married. And I fear for when grandkids are involved. I just feel so scared.