I too know someone (not well), related to my husband, whose wife left him for another woman, actually kicked him out and stayed in the marital home. She had brought her lover to live with her in the house while he was still there. The woman was someone known to them both, a relative of hers by marriage.
He tried to commit suicide, the Samaritans intervened and stopped him before it was too late. It was a cry for help really.
He left the house and managed to build a new life for himself. They shared the children who grew up fine. It was a very sad business at the time. Same thing happens with heterosexual marriages of course though I doubt a man or a woman would bring their new partner to live with them in the home with their spouse. At least not in recent times, it did happen in far gone days.
These things leave scars. It's not unusual for someone who has had a traumatic experience with a member of a particular group, could be ethnic, to mistrust that group afterwards. It can take a lot of time to rebuild trust.