He (Takaba) tends to show his ownership streak often enough though. Like when Sudou was crying on Asami's shoulder. He gets jealous when others pay Asami to much attention.
I think Aki may be fighting how much Asami's hotness effects Aki. Aki is too well aware of it, and so will not say it. Once in a while he thinks it though.
I think you also get a sense of how Asami's body turns Akihito on in scenes like this one, where he touches Asami. He's got a thing for Asami's chest:
http://www.mangago.me/read-manga/you_re_my_loveprize_in_viewfinder/mh/v07/c039/17/
And here, going right up the shirt:
http://www.mangago.me/read-manga/you_re_my_loveprize_in_viewfinder/mh/v07/c042/2/
Also, he's spent so much of this series in denial anyway, that's why you only get those few almost unwilling moments where he acknowledges that he finds Asami hot. He couldn't let himself think about it too much. Now that he's finally willingly on board for this relationship, maybe we'll get to see a more open Akihito.
Am I the only one who want to knock some sense into aki for not take a moment/deep breath and realized what a hottie asami is? One time, he acknowledged that asami have a great body and that's it. But, asami always expressed how adorable and cute aki is.