I don't know where to find more other said couple but if you are around them for most of the week - theirs lots of couples willing to invite you into their marriage sexually even if it's just for the wife's enjoyment. Been with a one couple for many years she's in her elder years. A long weekend starts with her dressed without underwear to naked by the end of the weekend looking at me with her puppy eyes.
Reminds me of a couple still around today, I'm the third person in the marriage - she's in her very elder years. He takes her first (happy with himself) then I come in to take over to finish her off. A great couple & trusted friends had lots of fun together, not to mention she has it often even it's just me her still dressed holding onto something.