There are women who say that if her husband asked for a paternity test, she would do it and also file for divorce. These women claim that it is a preach of trust and the man is accusing the woman of cheating. Okay I get that.

My question is, why is an accusation of cheating by asking for a paternity test any different to any other accusation of cheating?

Why don't these women also want to file for divorce if a man questions the relationship status of his wife and her "male friend"?

If a man is questioning the relationship that you have with a close male friend you might have, he is basically asking if you are cheating. Would you then ask for a divorce in this case because the man is clearly not trusting you with regards to this male friend? If a man asks you, why are you wearing your favourite and sexy underwear to work, he is basically asking if you are wearing it for someone at work or someone you will meet after work, will you then file for divorce because he asked why are you wearing that underwear?

If any partner ever questions if the other partner is cheating, should the accused partner then file for divorce just because there was an accusation of cheating?

Edit: Question answered to a certain extent. Seems like the other accusations are merely accusation of cheating and lying about it. While paternity is an accusation of cheating, lying about cheating, lying to the child about his/her father, lying to family about the father of the child, exposing the child to possible health risks that may be passed down through genes. While I understand this, divorce seems to be an extreme response though as you would be depriving the child from growing up in a 2-parent household because this one time the father questioned their paternity.