Okay, Ryo is really beginning to piss me off. He is hypocritical in his dealings (kinda). He tells Dee not to run off seeking his own justice, then does the same thing. All by-the-book, then goes postal (multiple occasions over the series).
Mostly, though... we are five books in (out of 7) and this guy can't even admit if he is even remotely interested in his partner. Dee straight-up told him he loved him and... nothing. He plays hot and cold and it is seriously beginning to annoy me. We were at the "make a decision" point 2 books ago.
He doesn't need to jump into bed with Ryo (though, at this rate, that will happen long before he even admits he likes men, let alone Dee), but Dee has no clue whether this guy even likes him. Ryo is so firmly in the closet, he's practically in Narnia... then gets hot and steamy and puts Dee in an awkward situation of having to back off and behave when Ryo is throwing himself at him.
Honestly, this shit happened last book, too. It's old. It's gone past slow burn and beyond playing hard to get. This is straight into red flag territory, now. Ryo is just being cruel. Dee has real feelings and Ryo is stringing him along, enjoying the attention, but too scared to commit. I'm about ready to throttle him!
side note: I really need to re-read RA-I