After a couple gets married, festive meals are held during the week after the wedding, and, under certain conditions, the special "Sheba Berachot" (seven blessings) are recited after Birkat Hamazon.
However, these Berachot are not recited during the week after a wedding if this is a second marriage for the bride and groom. If the bride is a divorcee or widow, and the groom is likewise a divorcee or widower, then Sheba Berachot are not recited in the days following the wedding. In such a case, the Sheba Berachot are recited only under the Hupa, and at the reception if it is held on the same day as the Hupa ceremony. For example, if two divorcees get married on a Sunday afternoon, and immediately after the Hupa, before sundown, they host a reception, then the Sheba Berachot are recited after Birkat Hamazon at the reception. If, however, the Hupa was held late in the afternoon and the reception was held at night, then the Sheba Berachot are not recited after Birkat Hamazon, since it is already the day after the wedding. This applies only if the meal began after sundown. But if the meal began during the day, then Sheba Berachot are recited even if Birkat Hamazon is recited after dark. It goes without saying that if Birkat Hamazon is recited after sundown but during the period of Ben Ha’shemashot (twilight), then the Sheba Berachot is recited.
Summary: When a bride and groom are both getting married for the second time, Sheba Berachot are recited only at the Hupa and after Birkat Hamazon at the reception if the reception began before sundown on the day of the Hupa. The Sheba Berachot are not recited during the seven days after the wedding.