There have been many thoughtful comments in this thread. I think part of what's difficult for you in this situation is accepting your thoughts and feelings for what they are, or part of what may be helpful to you is to work on being okay with what you feel and what you decide to do about it. I don't see anything wrong in not being able to let the little things go. I think if you can accept this is where you are right now, and feel good about being able to say what's on your mind-- especially to a T, I think being honest with other people is probably mostly better than the alternative. If you're going to err in a relationship, this seems to me the better mistake than withholding. Especially in a T relationship.

I get wanting to not make the same mistakes you've made before in relationships. I'm starting to date again after more than a couple of decades, which is super weird but also triggers these kind of feelings all the time about what did I say? Should I have said it? TMI? blah blah blah. I study the other person's response to see if I can figure anything out, and it's really hard. But two things are kind of on the forefront of my mind, something I learned in T. First, that relationships are hard and induce a lot of anxiety in me. I attribute this mostly to my CSA past and the aftermath of that. I feel more skilled and resilient in relationships now, am more relaxed than I used to be, but relationships are really about the long term. Little things said and done imperfectly will not matter much, and feeling that there is less at stake in any given moment is helpful to me. The other thing that may be more useful to you in the context of "little things" and ruptures is to get a little meta about relationships, to step back and think about what you're trying to accomplish in this moment (to act intentionally, rather than blurting stuff out), and then see which of possible responses might facilitate your goal. For example, if you are working towards trying to be more honest in the moment with T about what upsets you, then saying something about the little things rather than stuffing it seems a much better choice. I'm not sure what you do per se, talk about it or not, matters as much as the why. If, on the other hand, you are saying something about the little things because she won't change her mind about the thing she took away, either because you're still grinding away on that conflict and hoping she will, or because you are trying to punish her for the hurt you still feel, then maybe saying something about the little things is not productive to what you're trying to accomplish and who you are trying to be in a relationship.

The thing that helped me with T and relationships is a place to practice with low stakes, at least with the things I was able to say to my T, he didn't have any kind of "hot" response to. That's not always true with the people in my life. It's a chance to see what lies underneath the choices I made about what I say and do. So what strikes me in what you said, "I can't let the little things go" is of course you have a choice. No one, including you, is forcing you to say or not say anything. Maybe it would be helpful to you to explore the why with T rather than the what. In part because everyone owns what they say and do. In some ways, these are the only choice we truly have, not being able to control other people and their reactions and what the universe drops in our laps and all that. But you are the boss of you and how you choose to relate to people.