How does Ellis symbolically and definitively end his relationship with Michael in the novel, Tin Man?

Whe Ellis and Michael visit Villa Roche Rose in the summer of 1969, Ellis, away from Oxford, is more willing to explore his romantic love with Michael. He proposes that they simply stay at the villa, ignoring their train that is scheduled to depart back to England, but then quickly packs their bags on the day of their departure while Michael is running an errand. This action symbolically and definitively marks the end of their romantic relationship.