After constant arguments with my wife about anything and everything My wife had an affair with a black guy. When she first told me, i thought it was a lie to manipulate me (she had lied about this type of stuff in the past), then she sent pics, we almost split because of this. long story short, i fucked her friend (they initially split over this, later became friends again), ultimately we stayed together and now enjoy an open relationship
After the BBC sex, she told me that i couldnt sexually satisfy her like she wanted to be, she wanted a "real man to take care of her", her disastisfaction made her angry and create arguments. She also explained that she had had more fantasies and they progressively became more detailed, first these led her to buy black dildos (i didnt see any issue with this)
But even after we both fucked someone else, initially relationship was tense, from time to time (e.g. during arguments) she would bring up fucking BBC or the guy's name, she also bought more black dildos.