How to obtain evidence for a man's infidelity has legal effect?

Collecting evidence of the other party's infidelity needs to be obtained under the premise of legality. Evidence photographed and recorded in secret under the premise of legality can be used as evidence in court. Generally, the evidence that can prove cheating should be collected as follows: \x0d\ First, the investigation of extramarital affairs was suddenly exposed, and one party had no choice but to write a letter of guarantee and a repentance book to show his remorse, which was the key evidence of extramarital affairs; \x0d\ Secondly, prostitution, etc. Usually there will be police intervention, and police transcripts will become important evidence; \x0d\ Thirdly, after the unit verifies the extramarital affairs of employees, it sometimes deals with their life style problems, and the written materials handled are also an important evidence; \x0d\ Fourthly, letters, short messages and emails exchanged between the two parties. In addition to written evidence, such evidence should be notarized first and then submitted to the court; \x0d\ V. Photographs, audio and video recordings, etc. However, we should remind all parties here that such evidence must be obtained legally, otherwise it cannot be used as evidence.