Dealing with grief, falling in love, getting a job and wrestling with your conscience are all part of the human experience. If you are Peter Parker, you deal with all of these things plus the fact that you have super-human abilities. Thanks to a bite from a radioactive spider, Spider-Man came into existence and changed Peter's life forever.
Spider-Man has the ability to cling to walls, super strength, a sixth sense (a.k.a. Spidey Sense), perfect balance and super-human speed and agility. Peter created the Spider-Man uniform as a way to use his abilities for the good of helping the public while keeping his true identity a secret. Which wasn't as much a move of modesty as it was self-preservation as some of his adventures resulted in him being regarded as no different than the criminals he was trying to thwart.
Simply wearing a Spider-Man costume won't give you the same abilities that Peter Parker had, but if it does give you added confidence when it comes to dealing with matters of the heart then that would be enough to make him jealous.