In the Crucible, how do Proctor's motivations affect other characters in the play?

I would say that Proctor's main motivation is protecting
his family and his name.  He and his wife know he is guilty of adultery, though no one
else does.  He hopes the whole hysteria will blow over and he can keep his awful secret,
and in waiting so long, the accusations get out of hand.  More people are accused, in
other words, in part because of his motivation to keep his sin
secret.

Later he decides to come forward and put a stop to
the madness, or try to, and so this pits him against Abigail.  In his desire to save his
friends and especially his wife who also stands accused, he confesses, and this
threatens Abigail's own life as well, along with that of the girls who went along with
her.  This makes her more aggressive, defensive and she defiantly sticks to her
story.