I've been pondering this whole notion of comfort zones when it comes to reading, though I think we could apply this to any sort of media that we choose to consume. At first, I didn't even want to admit that I have them. I felt embarrassed by the idea.
After I thought about it some more, I started to look at my reading patterns. In reality you could call what I've done over the last few years as being in holding patterns. If I wanted to aim some judgement at myself, I'd even go as far as calling them ruts. What I started to question is whether or not I would equate those patterns/ruts as comfort zones. And I can admit that while both my more recent "ruts", Golden Age mysteries and M/M romance, give me comfort, I don't think they qualify as actual comfort zones, at least not in the way I choosing to interpret the whole concept.
Oddly, it's actually my romance reading that even has me pondering this whole esoteric concept. In my romance reading, I tend to get sucked into series, more than I do standalone novels. Though I read quite a bit of those too. What I've found myself doing in certain series is the issue at hand. Anytime a book has featured a relationship that is either M/M/F, M/F, or F/F, I've skipped over those books. At first I wanted to just shrug it off to not wanting to read sex scenes that involve women, despite the fact that I skim through most sex scenes anyway. Then I decided I have to see M/F relationships all over the place in every other form of media, that I don't need to read romances about it. That really didn't explain my skipping over the other two types of relationships though. That sort of left me with no other explanation than they make me uncomfortable, so I needed to figure out why. And while some of it is the sex scenes and the fact I have heterosexuality shoved in my face on a regular basis, I had to admit something I'm not all that proud of. It's partly because as a gay man, I don't understand those types of relationships. It's the same reason I've tended to skip over M/M romance that has a transman as part of the couple. Since I don't understand how they work, I chose to not read about them. I chose to not invest my time in something I didn't understand, nor cared to.
After I realized that, I had to take a hard look at myself. I began to wonder what other books, or even movies, I was ignoring because I didn't care/wonder about the perspective and story being told. What books were I ignoring because I don't understand the culture, religion, ethnic background, sexuality, disability, or world view that was at the heart of the story being told? That isn't something I can easily answer. All I can do is try to be more aware in my choices, and do my damndest to broaden my exposure. It's time to start pushing beyond my comfort zones, and maybe someday eliminate them altogether.
For the record, I'm now reading a F/F romance novel that is the fourth in a series I absolutely love.