Trying to justify his action now? or just trying to give an understanding of how he's like? Well doesn't excuse his action in the end.
Anyway what Ayane did is still fucking stupid. Revenge rape(?) doesn't change anything.
Eh, it seems like the author is setting it up that Ayane has repressed/rewrote her memories so that it was unambiguously rape and what actually happened is closer to the mess in this chapter - very very dubious consent with a side of coercion.
So help me I think we're about to go down the "pheromones made him do it therefore AYANE was the perpetrator all along!" route come onnnnnn we started so strong into psychological horror don't tell me we're just gonna veer into basic abo angst Dx