And I can see you don't understand humans. Men and women unfortunately, routinely leave people that treat them well. Why? Because they stupidly believe the grass is greener and they freemix. That is why freemixing is haram and even more so as a married man/woman.
He is a singer/entertainer and is in an industry that is a terrible environment. He freemixes, engages with haram all the time, and probably used to chill with the opposite sex. So, it is no brainer that he will eventually leave.
Only a silly man/woman marries a singer/entertainer.i wish the ex all the best, but she should have seen this coming. Men in the entertainment industry that freemix are not husband worthy.