I'm gonna tell you now Saki, give up on having Shishio for yourself.
Any woman that has an Akikan Protagonist focusing on her is gonna end up like these guys.
Honestly, I thought that the first girlfriend would be Shiina since she was the only one who really doesn't care who's with Shishio and thought that as long as she will always be with Shishio.
Anyways, Saki is also a good choice as the first girlfriend.