10 years is a lot, especially if you were 25 then and 35 now. She might have changed. People change, and change a lot, due to internal processes and external circumstances alike.

Since in one post you said both that your lines of communications have almost always been good (towards the beginning of the post) and that your biggest issue with the relationship is lack of communication (last sentence), it is evident that your relationship is currently in the state of flux. That is pretty much all that can be said with confidence. She might be testing waters or she might be, awkwardly rather, trying to see how you personally would handle having your own relationship outside of marriage if you ever have one.

Because these issues are awkward to talk about it for most people, since so much is involved - insecurities, ambiguities, uncertainty, self-doubt, doubting the spouse, and many more - this is not an easy topic of a discussion at the coffee table... at least not for a lot of people. Overall, I would be leaning more towards the hypothesis that she is testing waters and feeling you out because something has changed on her end (not that she has acted on it, but she seems to be contemplating changes). I am saying this because from what you have written, you, on your end, are not generating ambiguity and uncertainty; you are rather forthright and consistent. So unless she is trying to tease out how you would handle a hypothetical love interest of your own from many angles (which is possible if she is particularly anxious and insecure, but she does not seem to be from what little you have written), it seems that she has her own doubts and possibly temptations of a special kind and it testing how you would react under different scenarios. Since she volunteered info, it seems that she was trying to assuage your fears, and I think you were absolutely right to take that volunteered reassurance at face value, but on a moving forward basis, she might be having second thoughts about the marriage arrangement you are having. It does not mean that she does not want to be married to you, though. It is just that she might be communicating how her line of thought has changed by now, and is unsure of how to communicate it to you better. I do not think you are overdramatazing because you see a change of pattern - she says things that she did not say before. I would casually say something along the lines of: "Hey, lately you have mentioned a certain topic again and again - if you just want to sit down and tell me what you think, you are most welcome to do that." and see how she reacts. I would call a "certain topic" a "certain topic" specifically to create ambiguity for her and see how she resolves it. If she immediately gets what topic you are talking about, then yes, this has been on her mind a lot. If she gives you a blank stare, then likely you have been overly anxious and the topic is not on her mind a lot. If she gives you a blank stare, you can back off with: "Oh, never mind. It seemed to me that something has been bothering you a lot - never mind." And see how she reacts then. Basically, turn the tables and test the waters back to her.