Lena claims to hate Axel, but does she really? Maybe she says that she does, but on the route where you allow her to get turned on by the pictures, in her notebook, it's obvious she never really stopped having feelings for him. Just like Ian can still secretly have feelings for Gillian ( if you choose to allow it). On the surface perhaps there positions with Axel and Gillian are fixed, but in reality they never were. If Ian chooses to mastubate in Chapter 1, there is a clear inference, that his feelings for Gillian, are not as clearcut as he believes. And the way that Lena reacts, when she first meets Axel at the Restaurant, suggests heavily that she isn't over him yet. Why else would Ivy tell her not to get over-emotional when she talks with Axel? It's clear Ivy believes, that Lena might still harbour feelings for Axel?
This is of course dependent on your choices. On the path I follow, Lena and Ian never stopped subconsciously desiring their former partners. They both believed that they hated them, but this belief was false. They were angry with them, they were disgusted with them, but they never hated them. I think both characters start off in an ambivalent position, regarding their ex-partners, that can become either hatred or desire, depending on the players choices.
