Funny, technically, you broke this more than once in your OP.
Seriously, though, yes it can be a bit bothersome, but that’s a manner of speaking that it seems some people use. Personally, I’m the type to think things through and speak when I have a general idea where I’m going, but sometimes I get going on a stream of consciousness and those prompting questions that might otherwise have been in my head end up getting spoken out loud. Though, I don’t get into that stream of consciousness around other people terribly often.
For some people, though, they think by talking. So, yeah, they’ll ask a question that seems directed at those around them but isn’t actually. So, where I might internally wonder “Why did so-and-so do that?” then speak when I have a conclusion, some people just spit it all out. One thing I do like about it, assuming I’m genuinely interested in a deeper conversation with and getting to know someone, is that it exposes their though process, which means I have direct access to everything between A and Z and not just the conclusion, which can make it difficult to actually understand where they’re coming from. In fact, that’s part of why I don’t often put that stuff out, because it can actually end up being a very intimate sort of conversation, even if it’s not about something terribly deep, because you get to see the gears in action.
In fact, some food for thought would be, if this is something your SO does for everyone, then it just means she’s the type to think out loud. OTOH, if it’s something more unique to just you, it may be a sign of trust and intimacy that she feels with you and not others. And, if so, might be something you could appreciate more, in a sort of endearing foible sort of way.
As for Chefguy’s example, I’ve heard those people called Question-Talkers, and that’s almost always deliberate. A rhetorical question answered by the speaker can be used for impact from time to time, but some people just overdo it, and it seems to me that it’s usually a politician or manager trying to express authority or gain credibility or something like that. I will typically just mark them in the other column if that’s how they think they can gain either.