The singer, 29, is said to have been ‘obsessed’ with the TV personality, 30, after seeing her from across a bar in Los Angeles, with the pair going on to have a secret fling.
Abi branded Zayn her “Mr Grey” from sex-charged film Fifty Shades of Grey.
Zayn split from supermodel Gigi in October, after six years together. They share a 16-month-old daughter Khai.
The stunned television star, who joined TOWIE briefly in 2013, is said to have thought Zayn had broken up with Gigi when they began the fling and so ended things upon seeing the message as she ‘didn’t want to be his other woman’.