Flingee

He never thought of her as temporary or a flingee.

Source: wiktionary

Jay was trying to track down the flingees. Denise had never married, nor had she taken another long-term lover after Dennis's birth, though she had been seen in fashionable places with a variety of leading men.

Source: wiktionary

Brendy pointed out to me that a fling is different from an affair. 'A fling is definitely not serious—it's meant to be temporary and the flingees remain good friends afterwards.'

Source: wiktionary