happened to me a few years ago. at a BBQ, the gals were off to one side, the guys gathered on the other side of the patio. I stepped over to the beer cooler, close enough to hear my wife say, "no, (my name) has got a big one, very thick." her back was turned to me, the gals facing me glanced at me, and I noticed that my crotch was eyeballed a lot as the evening wore on.. I asked her on the way home what brought up my size and she said some of the gals were unhappy about their sex lives and wondered if a big cock would help and if they would cheat to find out. one gal asked my wife if she would cheat on me. and she gave the answer above.
another time, in a bar. my wife was approached and asked if she/I were into couple swapping. she knew the gal and her husband. she told the gal, no we were not interested. and the gal said, why not? you might be surprised. maybe find a big cock. my wife told her, she doubted she would find one bigger than mine. and the gal said, "that's what she heard." so little games are sometimes played.
my wife didn't go around talking about my size all the time, but when it did happen, it caused over curious women to be around. the 3 some offers, couple swapping, swinging became annoying. my wife's gf caught me napping nude one afternoon and that nite after couple drinks, guess what??? how about a threesome tonite???
so after awhile if my wife was specifically asked my size, she just told them that overall, I am a big man(which is true) or her more common answer is I am a good husband and lover.