Because their society has a completely different attitude towards sex than ours. And because they have a genetic predisposition towards engaging in sexual activity in times of high stress and Satouru was there when Shun wasn't.
I think they still went ahead and did it off-screen. You know how they were in that nest thing and gave the guard a fake haythatcher egg to make him go away?
I'm pretty sure they didn't either, but since there was off-screen time, and a HUGE time gap I suppose it's mainly for the audience to guess, I haven't read the novels either so I can't go from there. Oh well, this is such a small piece of the plot that I don't know why I'm questioning it .. just feel bad for Shun ;__;
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u/[deleted] Mar 09 '13
Wait, I'm confused. I'm pretty sure Saki loved Shun but why did she have sex with satouru then?