Started this way myself. It worked until I drowned my friend in cum.
I have never had that exact experience...that said, over the many years, there have been some times where the wife of another really humongous endowed guy, having us both hard and both of them seeing for the first time a hose thicker and longer than the wife's husband, the wife asked me to shoot at least one of my loads on her husbands cock or on his face. I have only done that if both wanted me too and she held me and there was no oral from her husband. Each time the women told me that they had spent years watching their husband be the 'biggest" and fucking all their family and friends and they "put up with it rather than lose him"...and also watching their husband doing a bit of the same thing to other guys who had big dicks and not just average or small endowed guys...and it was fun for them, the women, to finally see it happen to their husbands. Those are the same women who always were the most vocal during sex about talking to their husband about what mine felt like to them....and they ALL insisted their husband fuck them after I had pulled out after several loads inside them...and they all seemed to delight in telling their mates just how stretched they were and how the husband had inside them then.
I have never married...but I have learned lessons from all the married women I have been with...and one is that, especially when the other guy has a whopper hose...I can never assume anything about the dynamics of the couple, and what desires and long simmering resentments or needs they have toward each other. I just try to smile and be nice and fuck the best I can and not be anything but the very nice guy with the hose they like.
I guess what I am saying is that as a life long nudist...and encountered some of these couples at nudist resorts and nudist beaches...or at hugely attended "lifestyle" conventions....I am a happy person who tries to always be upbeat and drama free...and sometimes the drama that some couples, not all, but some...bring to sex can be not worth the effort. Interestingly, most truly extreme endowed guys...once they get over the shock, are mostly, but not all, fine with the surprise of meeting someone larger....but the wives...the girlfriends...sometimes they see the most upset and even angry...as if their "social" place or own image and "self identity" of being the woman with the guy who their friends and family all think married "superman" is not the same anymore...and some of those women then go in to drama mode...at either their husband...or sometimes to me.
Women are soooooo complicated sometimes...LOL.