I think 79pmooney covered most of it. About fixing flats on the road: I know you said that this is beyond your comfort zone, but let me ask you: would you rather take the time to develop the skill (I learned at 7 years of age, so there's no way you can't learn this), or would you rather continue to have to take multi-mile hikes when something goes wrong?

Also, to address a couple of things that 79pmooney didn't:

Most flats happen on the rear tire, so it isn't unusual for flats to keep happening on the rear. I've had, maybe, 1-2 flats (max) per year for the past 30+ years, and I can only think of two that were front flats - both were pinch flats caused by hitting large-ish rocks (therefore, pilot error).

There are theories as to why this is so: supposedly, debris naturally lies flat on the road (gravity, rain, wind cause the debris, for example a piece of wire or a piece of glass) to lie flat. In the case of a piece of glass, it gets turned over until the "points" dig into the road and hold it with the smoothest side up. Then, your front tire runs over it, it gets kicked up so that the pointy ends can lodge in your rear tire.

So, don't blame your poor rear tire, it is likely innocent.

Second: I don't think anyone mentioned tire liners. You can google "bicycle tire liner" to see what I mean. I personally have never used them because, as mentioned above, I get at most 1-2 flats/year.