I'm a newbie too, but I thought that I should add that, while you should absolutely do what feels right to you, a higher cadence does have it's benefits. With practice, many people find it easier to maintain an even pace and high cadence riding is widely preached, so it's not surprising that someone might steer you towards that. However, you definitely should not be spinning so fast that you are bouncing in the saddle or feel out of control. I seem to like 80-85 rpm the best, which is far from spinning wildly but is a pace I still have to think about to maintain at my current riding level. I had to move down a gear to maintain the rpm (I used to ride at about 60 rpm) but after a few rides, my overall pace has increased.

On other hand, mashing on a higher gear does have the potential to hurt your knees, even when you don't think that you are pushing that hard. Over time the effects can add up. Not that you are mashing a high gear, but it’s something to experiment with. There is a personal balance that each rider must find for themselves.

Also, there is some overlap of the gain ratios from the small to large ring so depending on what gain ratios you feel comfortable riding in, you might be able to dial in a similar gear using the small cog. You just have to move your chain on the rear cogs appropriately so that you don't jump down a huge percentage and spin wildly. I have found that knowing the gain ratios for my gearing really helps.

I’m a collect evidence kind of gal so personally I would look up your gain ratios and those for his bike and compare. Maybe he doesn’t realize what your gearing feels like and how it might be very different from his. Of course if the evidence does not support my position . . .it disappears before he sees it.

Good luck getting your BF to lay off!