It seems more complex to me, since, for example, if I express that she hurt me by doing something, she is very sincere in saying sorry and she does feel bad about it. But that usually happens only in that moment and when I want to discuss it afterwards (I am for talking openly about problems and solving them together), she is unable to do that. She just shuts down and ignores the topic and if I mention it multiple times, she gets upset.

If it's really serious, she then writes me a message online, but that's only when she really needs to vent and it's not a civil conversation anymore.

Recently, I even asked her to tell me if there are any things she doesn't like in how we run our household or the relationship in general, so we can fix it, and she couldn't name any out loud, although she obviously had them in mind. She says I have to pick up the clues in the moment when she expresses her dislike of something.

I don't think she's putting me down consciously, maybe she doesn't even notice. She appreciates many things about me, it's just that she is so different with other people than when we are alone.