The Girl in the Plastic Bubble

Lilith informs Frasier that she wants to spend a year away from him, sealed in a biosphere with her lover. Frasier reacts to this like any trained psychiatrist - he steps onto the ledge of Melville's and threatens to jump if Lilith leaves him. Lilith and Sam manage to talk him down, but Lilith insists their marriage is over. Once Lilith has gone, Frasier's friends rally round in support of him.