<human>: Summarize the given text in a few sentences.

My SO and I have been dating for just under one year, and moved in together 2 months ago.

Since that time, I have noticed that my SO really enjoys walking around in her "pajamas" late at night. She doesn't really make any effort to close the curtains or shut the blinds, and I'm certain that she knows how easy it is to look into an apartment when it is dark outside, and all of the lights are on. (Though the windows/glass doors in our apartment do not face any particularly busy roads, they are still trafficked on a semi-regularly basis, so there's certainly a risk of being exposed.) I put the term pajamas in quotation marks because she tends to walk around in her bra and a thong... 

While I love that my SO is comfortable with her body, and think she looks beautiful in her "pajamas" of choice, I'm less enthused by the fact that she seems to be okay with random passerby catching a glimpse. On one such occasion, I jokingly asked her, "Aren't you going to close the blinds before you take your clothes off?", and she just sort of shrugged her shoulders. I find this hurtful, as I do not think that it is appropriate for other men to see my SO in her underwear, or for other women to see me in any state of undress. (I realize that this might make me "old-fashioned", but everyone has their own understanding of what is and isn't "exclusive" within a relationship, and this is something that is important to me.)

Am I being totally unreasonable, or am I justified in being uncomfortable with this? How can I tastefully bring this up as a topic of discussion without upsetting her?
<bot>: SO routinely walks around in her underwear with the curtains and blinds open, and I'm sure random passerby have caught a glimpse. This makes me uncomfortable, and I'm not sure how to go about addressing it.