I guess you could say I'm going through a period in my life where I'm stubbornly refusing to go along with the conventional wisdom that one's sexual relationship absolutely has to align with one's IRS filing status.
So let's see if I got this right. If your wife's libido drops because of menopause, then it's time to switch your property, IRS status, step kids, in-laws, etc. And if the new wife has a drop in libido, switch all those things once again, even though they have NOTHING to do with sex. And the chances of that are high. First marriages last only to about the 12th year (median). Second marriages don't even last that long.
