Gawain the Good Guy

Gawain is faced with a woman who is throwing herself at him, but he remains "gracious--and also on his guard" (443). Clearly, Gawain is a good guy as he consistently toes the line between gracious and cautious. As the Green Knight confesses his plan, Gawain says on page 472:

"But it's no great wonder whenever a woman outwits 

A man and leads him away to mourning or to madness,

For Adam himself was led astray by a woman" (2414-2416). 

He lists other men who were misled by women, but why are women to blame in this case if the Green Knight literally just admitted that it was his own plan? I might be missing something, but it seems like Gawain is unfairly blaming the ladies for executing a plan that was conceived by a man.