Were you able to say that you only felt able to share if you were explicitly asked to do so? That seems like an important issue in the therapy. If you didn't feel able to proactively share your feelings or thoughts, you needed to at least be able to talk about your experience of being unable to share. Otherwise, your SO and/or therapist are put in the position of mind reader and that will never go well.

I don't like couples therapy and I definitely didn't have a good experience with Relate so I can imagine that your therapy wasn't great.
However, I also know from my individual therapy that it is comfortable to blame the therapist, project your stuff onto them, rather than explore your personal responsibility and internal experiences.