My wife is definitely more sexually active, and I've lost some steam over the years, but since she is in her late 50s, finding a third has gotten a little more "challenging".
six for sure, 3 plus myself (twice) when I was with her, but we got seperated a few times that day/night, so there could have been more than the one I knew had her alone in our room.
My wife says she likes any size, but she is interested in trying one thicker than I. She has had a guy longer than I (8), and REALLY enjoyed it, but said she wished he was thicker.