The 'I accept quote' button cannot be pressed while logged in as a user, to avoid accidental quote acceptance, so to accept a quote on your Bride's behalf head to their WedQuarters by clicking the globe icon from the Bride Card.

Under the 'user buttons' you'll see the text 'Accept Quote on Bride's behalf? Click here if so'.

This will then show the 'Accept Quote on Bride's Behalf' button.

This option will only show if the quote has not been previously accepted.