I can't believe that they expected you to pay for parts of your cousin's wedding. Seriously? And after you were hosting the rehearsal dinner? Jeeze. People are amazing.
I remember telling my DH that on the day of the wedding, nothing else matters but that you enjoy the day. A wedding can be the most elaborate and beautifully decorated event on the planet, but if the bride and groom don't seem happy, it's just a big FAIL. We didn't let anything bother us on our day and it we'll always remember it as one of the funnest days of our lives.