The Sun reports that the supermodel [Naomi Campbell], who is thought to have dated the Saudi businessman last year, is disgruntled the singer, 29, and Hassan have fallen so hard - as she hates feeling 'second best'.
A source revealed: 'They're both formidable women. No one knows exactly what went on between Naomi and Hassan but she certainly doesn't like being second best.'
Adding that the Work singer was in too deep to stop the romance, they continued: 'Rihanna is someone that falls hard for someone, and nothing can get in the way.'
The singer, 29, is dating Hassan Jameel - a Saudi businessman who is currently the deputy president and vice chairman of family business Abdul Latif Jameel, one of the biggest companies in the world.
The company owns distribution rights for Toyota cars in Saudi Arabia, a deal that has helped the Jameel family amass a fortune estimated at $1.5billion - which Hassan will one day inherit.
His family also owns a soccer league in Saudi Arabia, called the Jameel league.
A source told The Sun: 'This relationship is the real deal. Rihanna has told friends she’s in love with him and seems completely smitten.
'They’ve been spending a lot of time together away from prying eyes and are really serious. They’re really enjoying each others’ company.'
Hassan was previously spotted looking affectionate with supermodel Naomi Campbell in July 2016 at the British Summer Time Festival in London.