Aqua wasn't really interested in dating anyone but when he met you...

...someone who resembled Ai so much, right down to her starry eyes and smile.

He knew you were an idol and he was worried a bit, he was afraid that your relationship might come out and someone just like the stalker that killed his mother might come after you too in jealousy.

But hes older now, he'll protect you...he won't let it happen again.