We have somewhat the reverse going on so I thought I'd drop this in.
Those that follow me on snapchat / fetlife see this happen, so that cuts out all the BS.
I'm in a cuckcake relationship, those not in the know, she gets off on me fucking others. I'm still an active bull to 2 couples and have two playmates, the deal is always the same, first meet shes there to watch, so the girls know she's around and then from then on she gets off seeing the Snaps, and when I come home, we fuck recounting the night. It's all good. Sex with me is always long, I'm 44 now and been having sex a very long time so I like long sessions, it's something that the GF can't always handle.
She has always gotten off on guys getting off over her, we've had sex in public, she gets off seeing guys cum quickly, jerking while watching, there's something about 'disappointing men' that rocks her world.
Recently she asked if i was ok with her fucking an old FB and I agreed; you don't fuck couples/singles yourself and then not allow the same, after all, we are equals. The FB is much smaller, and she wanted to see maybe what he felt like etc. etc. fair enough. Sure the jealous monster kicked in before a dose of 'don't be a jerk, look how many others you fuck' and a reminder of how secure we are.
Sure enough, they fuck, it's a 20-minute one and done, and she's left 'unfilled'. Next day we see each other, and I have to say it's the hottest fuck we've had for a while. Everything from the groping, unveil, handjob, oral was all about appreciating the weight and size and then come to the fuck she just needed it deep. Nothing soft about this she just wanted to feel stretched and full.
All it's done is reinforce this is the cock for her, and that disappointing men are fine.... at arm's length.