Have several a mid 30s to mid 40s FWB ie 20+ year age gap. Generally they want a more mature playmate who understand the difference between making love and vanilla "wham bam thank you mam" sex that they tell me is typical of their own demographic. They enjoy the idea of being an object of lust, not necessarily love. They still want long passionate, pleasurable foreplay and want to be blissfully spent by the end and then just part with those memories at the end and no strings.
Many are in a long term relationship and their partners are also friends, know and encourage our playtimes, and in one case even babysits while we play.