The Other Cow is an easily titillated Cow that feeds on jealousy and gossip. She may be easy on the eyes but she has an agenda – to make it socially unacceptable for anyone to divorce in order to marry a new person. She is the most judgemental of the Cows and the most wrathful. Guilt and shame are her preferred tools.
Tipping over the Other Cow is not a defense of piggishness or deception. This Cow only insists that it is always wrong to leave a marriage to be with a new person.
Most people would agree that adultery is bad. Adultery almost inevitably involves deception and betrayal, and even if you think that divorce is sometimes okay, you are unlikely to agree that it is acceptable to unilaterally break your marriage vows without even having the decency to inform your spouse.
On the other hand, if you think that divorce is sometimes acceptable, you are unlikely to have a strong opinion about whether or not it is okay for people to get married a second time. The idea that a divorced person can remarry is not offensive to most people in our society.
It may not seem obvious at first, but between remarriage (acceptable to most of us) and adultery (unacceptable to most of us) lays a long continuum. The continuum consists of the time when the new partner appears relative to the end of the marriage. If partner #2 shows up while the marriage is intact, we call it adultery. If partner #2 shows up years after divorce, we call it remarriage. If partner #2 shows up while the marriage is on the rocks but before the divorce decree is signed, well, it’s not clear what to call it, other than messy.
The Other Cow, like all Sacred Cows, opposes anybody getting divorced. She therefore exploits our society's negative feelings about adultery to pressure people into staying married. She knows that when a couple goes public about their split, the existence of partner #2 will be revealed, inciting gossip and social disapproval. This is a disincentive to separating (and also, ironically, an incentive to lie about partner #2). The Other Cow wants to make sure that nobody thinks too hard about the distinction between cheating and leaving a marriage to be with a different partner, because she wants to leverage society's disapproval to stop divorce.