Temperature Variability

Hi!
My husband and I have been “eating for heat” for about 2 months now. My temperature goes up and down rapidly day-to-day and throughout any given day. I can wake up with a low temperature and then be up to mid 99s by the afternoon. My husband, however, has a steady 98.6 temperature, with maybe .1 degree variability. What causes this? Why the difference?

That’s my main question for now, but for those of you who are interested, here’s a little introduction (seems self-indulgent but I love reading everyone else’s):
I have been struggling with my health for about 5 years now. Each decline in health was actually preceded by a period of restrictive eating (in hindsight). The worse I got, the more restrictive I became, the worse I got. In the pursuit of health, I have been on the following diets: vegetarian, low carb, dukan, paleo, slow carb, GAPS, bulletproof, elimination and probably more.
I was totally humbled when I started eating the food like a normal human being – and feeling better. I have gained some weight but I’m remarkably okay with it, because of all the good things (increased libido, clearer skin, decreased anxiety, being warm, etc). I actually feel better about myself.
We are in the process of selling all of our possessions and going to do some long-term travel. We can work remotely, do some volunteer work and live in a warm climate – something we have dreamed about for years.
Okay, thanks for reading! And thanks for all the valuable information on this site and forum!