In as much as Ji Yao enjoyed being swept off his feet like a princess and carried over the threshold like a newly wedded couple his face wasn't thick enough for him to be carried around the imperial city in such an inglorious manner.
After taking two steps past the imperial city gates he whispered in Rui Fei's ear, "You can put me down now... everyone is looking."
Rui Fei pursed his lips staring at those magnificent eyes through the veil. He truly enjoyed parading around with Ji Yao in his arms because in a way he would be showcasing his relationship with this man to everyone. In simple terms, he was literally saying, "MINE!' without actually saying it.
So based on this conjecture he was basically going through an endless stage of a phenomenon classified as the toddler syndrome a.k.a 'mine' phase. Since he couldn't have what he wanted he could only think of another way to make this memory last longer.