PLEASE- SOMEONE!! HELP!!

Matthew is certain that he needs a spiderman muscle costume- it's all he's been talking about for 3 days now! He threw himself on the floor in a puddle of tears at Sara and Stuart's because Stuart didn't have one in his closet... all day today he's been asking me to make one for him- buy one for him- get one off of the computer and make it come out of the printer... make his clothes into a Spiderman costume.... I know sometimes kids have to want things and deal with not getting it- but for days?? And why does it have to be so hard on me anyway.... I've already been though this as a kid... I have to do it again???