Michael Richards (Kramer) actually hurt his back when Jerry (Jerry Seinfeld) tried to free him from his jeans.
This is the second time that George has made an inadvertent comment that breaks up a marriage; he also broke up Robin and Michael's marriage in The Good Samaritan (1992) with his "God bless you" comment.
At around 11m30s, Elaine and Jerry are congratulating George for his role in breaking up Beth and David and do a little dance. Elaine adds in a few awkward dance moves at the end of it, which may be the first glimpse of the Elaine Dance that becomes iconic later in the series.