how awesome that you're so attentive to your pillion! Women do get cold quicker than men, here's why:
As an ex-pillion rider (Paul and I did some 30,000km around Europe on his Super Tenere a while back), here's my experience:
- I ALWAYS got colder wayyyy before Paul did. Layers, however many, however great quality, just didn't do the trick. I cold colder quicker because women have a lower core temperature and usually, slower metabolism, plus as a pillion, you're not really doing much while the rider is, you know, riding. Depending on the size of your windshield, it's possible that you're more protected from the wind too.
- this continued even when we got back to two bikes. Riding Labrador and Newfoundland in Canada, or on off the road, Paul was always quite comfortable with just a base layer and a thin merino layer whereas I was always freezing even with five layers on. So, I got the First Gear Heated Jacket - and never looked back since. I have been wearing it for two years now, no issues. Heat can be regulated, so you can have it on "slightly warm" through to "blistering hot" (always make sure you're wearing something with a higher collar underneath, the collar can feel like it's burning).
- consider increasing your stops. Even if it's just for five minutes, to walk around a little or grab a coffee (especially grab a coffee!:) ) Getting off the bike and walking or getting a hot drink more often can make a very big difference. Again remember, riding a bike as a pillion is very different: you're not moving much, not putting your foot down at stops, not concentrating as much on the road, not as much in tune with traffic, environment, surroundings, etc - your sole job, basically, is not to interfere with the rider, and that puts a different kind of demand on the pillion.
- food! Lots of good, hot food:) I always, always got hungry before Paul did (and I have heard other pillions report the same) and it really sucked because most of the time, I was both hungry and cold at the same time. Not a pleasant situation at all! Always have a nice hot meal before leaving and make sure your pillion isn't getting hungry on the road. If she is, grab a hot drink AND a nice hot snack at stops.
- do you have intercom? Talking while riding can be a great boost for morale, unless of course you both prefer your own quiet helmet zen.
- what are your destinations? If your pillion rides with you because she enjoys seeing new places and learning about new things more than the riding itself, can you make your routes more varied, visit places that are more interesting to her, or stop at her favorite coffee shops or bookstores or countryside locations?