The couple's car, described as grey, was seen being driven dangerously in the build-up to the assault after it had stopped in a lay-by near the Jet petrol station in Lebberston, near Filey.
North Yorkshire Police are appealing for witnesses who saw either the car moving or the assault itself at around 12.30am on Saturday July 10.
Both parties were injured in the incident. The man was found by police near the car and detained, before being released under investigation while enquiries continue.
Officers are trying to establish the 'full circumstances' surrounding the assault and have appealed for anyone with dashcam footage or who saw the car travelling between Scarborough and Filey beforehand to contact them.
Anyone with information should contact North Yorkshire Police on 101, select option 2, and ask for Sammie Osborne. You can also email [email protected], quoting reference number 12210156700.