omg I feel this so much!! I'm an aries too and I dated a cap for almost a year

the pace thing is SO real. I had to learn that when he went quiet it didn't mean something was wrong, that's just how he processes stuff

once I stopped reading into everything it actually got way better

This is such a classic Aries-Capricorn dynamic. Looking at it astrologically, you're both cardinal signs which actually gives you more in common than people think - you're both initiators and you both like being in charge.

The tension comes from your ruling planets. Aries is Mars (fast, direct, now) and Capricorn is Saturn (slow, deliberate, long game). He's not disinterested - he's just building. Caps don't invest in things they don't see a future in.

The question to ask yourself: is slow-and-steady something you can appreciate, or does the pace genuinely make you unhappy? Both are valid answers.