i'm going to go out on a limb and suggest that about 40-50% of husbands in couples where the male is listed as straight will dabble in m2m fun behind closed doors. Also this tends to be truer of more mature couples with more years in the lifestyle. Lots of couples tend to list hubby as straight so as not to turn off other couples. Our experience with single males suggests that guys who list themselves as bi do in fact get quite a lot of interest and quite a lot of action,, and don't be surprised if a lot of interest does in fact come from couples where hubby is listed as straight.