@stilgar
@AthalosJ
I'm pretty sure he's doing these things because he's being defiant. As in he wants to do whatever he can to make Midou upset, to do whatever he can to defy her. He's convincing himself he's in control of his own life. So by sleeping around with lots of women he's effectively giving a big middle finger to Midou, saying "see b*tch? you don't control me".
The thing is, it's a duality, his entire life is dictated by Midou, he's earning money so he can hire investigators to track her down, he's sleeping around in a pitiful attempt to try and defy Midou. She's literally the singular purpose in his life, in a way he's absolutely obsessed with her, albeit negatively.
Also interesting is at first he tried to blame himself, and shut himself in, until Yotsuya warmed him up again, and then Midou proceeded to shatter that once again. So this time he's trying the opposite reaction, hatred and anger, not at himself but at Midou. The opposite of what he did when he shut himself in.
@Asingh89
that's what he's trying to do... he couldn't find her. Its kind of explained....