In the book The Crucible why does John Proctor hesistate at his confession being written?

John finally realizes that there is good in him, and that the only way he can feel good about himself is to not sign his name away. He says dramatically, "Because it is my name and I can never have another." He does not want his children to bear the shame of having their father sign his name to that which is a lie. He wants them to live free and proud without him, rather than embarrassed with him had he made confession to something which is a lie.