Once Damis's out of the room, Tartuffe tells Orgon how awful Damis has made him feel.
Orgon runs to the doorway through which Damis has just exited and shakes his fist, cursing his son some more.
Tartuffe tells Orgon he simply has to leave, that he's caused too much trouble for everyone.
Again, Tartuffe proves himself a master of reverse psychology…or maybe just proves that Orgon is a buffoon. Or both.
Orgon talks Tartuffe into staying – as if he really needed the encouragement.
When all that is settled, Tartuffe makes one more request: he tells Orgon that he simply must avoid Elmire, just in case, you know, something might happen.
Orgon will hear nothing of the sort. He wants to get back at his mean, deceitful relatives. In order to do so, he tells Tartuffe to spend as much time as possible with his wife. He also decides to make him "his only son and heir"; he matters more, he tells Tartuffe, "than wife, child or kin" (3.7.21).
Tartuffe is cool with the arrangement; as far as he's concerned it's God's will.