Reply #120: I would say this has more to do with social pressure,

[PetraPooh]

than trust. If a person is upfront and honest about infidelity, or conversely it is agreed in advance to NOT discuss it at all; marriages seem quite resilient till "helpful" friends, family, and neighbors overwhelm the situations with their opinions. In societies where polygamy is practices, infidelity is NOT a cause for doom and gloom, just fact. Again, religion not reality seems to flavor your social prejudices.