There are varying texts of the conclusion of the Birkat Erusin, the Beracha recited at the beginning of the Hupa ceremony at a wedding. One version of the text is "Mekadesh Amo Yisrael Al Yedeh Hupa Ve’kiddushin" ("Who sanctifies His nation, Israel, through [the institutions of] Hupa and betrothal"). According to other sources, the final word of this Beracha should be "Be’kiddushin" ("with betrothal"), meaning, with a "Bet" as opposed to a "Vav."
The Bet Yosef (commentary to the Tur by Maran, author of the Shulhan Aruch) notes that the text of "Hupa Ve’kiddushin" does not accurately reflect the Halachic process of marriage. The process begins with Kiddushin – betrothal, when the groom designates the bride as his wife. The term "Hupa" refers to the end of the process. It would therefore be inaccurate to refer to the wedding as "Hupa Ve’kiddushin," which implies that the Hupa occurs before the Kiddushin. Followers of this text would have to explain this to mean, "Hupa and the Kiddushin which takes place first." Of course, this seems to be a very strained reading of the phrase.
Therefore, the more accepted view – which is indeed the position of Hacham Ovadia Yosef and the custom in our community – is to recite the text of "Hupa Be’kiddushin," which means that the Hupa – the marriage – is done through the process of Kiddushin. It stands to reason that this was the original text, but since some people pronounce the letter "Bet" as a "Vav" when it is not punctuated with a Dagesh (dot), the word was at some point mistakenly spelled with a "Vav."
It is customary for the groom to break a glass under the Hupa upon the completion of the seven Berachot, to commemorate the destruction of the Bet Hamikdash. A glass is used for this purpose to indicate that just as a broken glass can be repaired, similarly, we are confident that the shattered state of Am Yisrael is reversible, and that we will be "repaired" through the final redemption.
This custom is reminiscent of a number of stories told in the Talmud (in Masechet Berachot) of Rabbis who would shatter an expensive glass at weddings when they saw the guests celebrating too wildly. As the festivities began getting out of hand, the Rabbis would break a glass to temper the aura of giddiness and restore a degree of sobriety. Breaking utensils for this reason, and for the purpose of commemorating the Temple’s destruction, does not violate the prohibition of "Bal Tash’hit" (wastefully ruining valuable goods), because it is done for a purpose. The prohibition of "Bal Tash’hit" applies to destroying usable objects for no constructive purpose. It is permissible, however, to break a glass to calm the mood of overly excited wedding guests, or to remind people of the tragedy of the Temple’s destruction.
Summary: The proper text for the conclusion of the Birkat Erusin recited under the Hupa is "Al Yedeh Hupa Be’kiddushin," as opposed to "Al Yedeh…Ve’kiddushin." It is customary to break a glass under the Hupa to commemorate the Temple’s destruction. This does not violate the prohibition against wastefully ruining valuable goods, since this is done for a worthwhile purpose.
