[Whewt22]

Tousens reaction to Gin, almost implys to me that he doubts Gin. Using anything as an outlet to question his motives. Hense drzorbas statement.
Gin is sadistic, but his constant search for a friend or approval may be the only thing keeping him attached to Aizen. He befriended him as a child, but their not bound by anything other than a friendship through destruction.

If anything I leaned away from Tousen being the one to betray Aizen, to Gin.
Or im reading too much into things.