Juggling 30+ girls on a continuing basis ain't easy, even for someone strongly suspected of being a demigod.
You can keep all of them happy with 15 days and still have time for quests...you need the Waytones and are sleeping at a different place essentially every night but I've done it. That might not suit your play style, though.
There's always the Affection Cheat, which turns off Affection loss entirely. (Except for Obeah who has quests requiring her Affection to bottom out...)