I don't think that's the case.
When they told him he couldn't marry, he was holding his bride and she was smaller than him.
Also, compared to how tall he is in comparison to the human and how tall the others are in comparison to the human, I think he's just about average, perhaps even on the tall side.
I was joking more than being serious.
Oh. Sorry XD It's hard to read tone in an online message haha
No worries!
Maybe the real reason the Titan needs a human bride is the Titan is super-teeny tiny for his kind. It's massive to humans, but only a titan pinky in their world. Let's hope this for the MC's sake.