If he just wants a casual fling, he's not the guy for you.
The Sun
Occasionally, a casual fling will turn into something else.
Times, Sunday Times
He may have thought 'the odd casual fling never hurt anyone' but he'll discover there can be a downside.
The Sun
They tend just to suit people who are out for a casual fling.
The Sun
Not a lifelong commitment, but no casual fling either.
Times, Sunday Times