There's a certain logic to have all the LIs on the CHICK side.
Sage was on the DIK side at the begining, fuck buddies is ok on the DIK side, but as soon as the relationship evolves toward something more, you need comitment and comitment is more on the CHICK side or you have an "open relationship" like Tommy/Heather.
Let's face it the MC is a young introvert, poor guy who doesn't impose himself. As he often say, he's more a listener than a talker.
He arrives in college as a white sheet of paper in a new environment and he can completely stay true to his education and be respectful playing a little and ok for a commitment when and if the occasion is there.
On the other side he could just become a player and live the full DIK college experience, sleeping around, banging every possible chick he can and even if sometimes he's tempted by a more stable thing, rebound guy scene, he just continue to be a player, blocking the possibility for something else.
(ok not easy to write in a foreign language , hope it is still understandable)