on My Head
After their wives exit (at line 148), Ford and Page discuss what Pistol and Nim have told them. Page is confident that his wife will only have sharp, scolding words for the old knight:
PAGE: If he should intend this voyage toward my wife, I would turn her loose to him; and what he gets more of her than sharp words, let it lie on my head.
FORD: I do not misdoubt my wife, but I would be loath to turn them together. A man may be too confident. I would have nothing lie on my head. I cannot be thus satisfied. (160-65)
The expression “let it lie on my head” means that Page will have himself to blame if his wife and Falstaff have an affair. But Ford takes the expression to mean also that Ford will have cuckold horns lying on his head. Thus, Ford’s response indicates (1) that he will take action so that he will not have to blame himself later and (2) that he will make sure that he does not wear cuckold’s horns upon his own head.