I use this cable to reduce strain on my phone's USB jack:
(xDuoo X-C12)
Though obviously that requires a thumbdrive-style dongle with removable USB cable.
Alternatively, ddHiFi makes a bunch of stubby little adapters like this:
Those should reduce strain as well.
Regarding wear and tear on the port, I can't say much. My four years old phone is still going strong, though I'm not a heavy user.
Edit: another potential port saver: ikko itm05