In the 1500’s, the garter was related to the consummation of marriage. The bridal party would sneak into the newlywed’s bedroom for proof that the marriage was consummated. While they were in the room, they would take an item of the brides clothing, usually the garter, for good luck.
Due to the obvious invasion of privacy, tradition changed. After the wedding, as a sign that the woman was no longer available or no longer free to flirt, she removed the garter and gave it to her groom. The groom then tossed it to his groomsmen symbolizing the “last good-bye” or the last bit of leg they would ever see from her.