Locked in Chastity

Jamie games too much, ignores his girlfriend Kim, and doesn't notice their relationship falling apart until William shows up to make the neglect a lot more literal.

The setup is simple: an inattentive boyfriend, a neglected girlfriend, and a third party who's happy to step into the gap he's leaving. Whether that gap closes or widens is the whole story.

This is a kinetic novel, so there's no branching to manage and nothing to optimize. You read, watch the CGs and sprite scenes pile up around Jamie, Kim, Diane, and the rest of the cast, and let the camping trips and school-setting drama play out on their own terms. No choices, no routes, just the slow unraveling of a couple who probably shouldn't have lasted this long anyway.