Ok, I know you're never supposed to ask a lady this, but just how much of a lady of substance is she. I have a couple of riders down here that are 6' to 6' 6 " and about 225 lbs that are hard riders and never have this problem. Maybe get the wheel rebuilt with straight 14 gauge spokes. I believe this build is good for up to 250 lbs. Make sure to run that tire at 5 lbs. below max pressure. This should help.
Marc