My blood pressure dropped low while on Phase 1 and has stayed there in maintenance. (just now it is 81/63 and I have gotten readings in the 80s at the doctor office, too)
I echo the advice on getting enough salt.
When I commented at the doctor's office, the nurse said I was likely dehydrated (and I have dropped my water intake considerably, which I need to work on).
Until I got used to it or balanced things out, I thought the low blood pressure mostly made me tired. I remember that the dizzy/light-headed feeling eventually got better, maybe by about the third month, so maybe you are turning the corner. At that point I was having 1/4t salt at lunch and 1/4t salt at dinner, drinking 96 oz of water every day, and taking the required vitamins and minerals.
Do you think your salt, water and supplement intake have all been consistent?
Could something besides the diet be at play?
Are you using IP products or alternates? Alternates often have vitamins in them which could be throwing electrolytes off, as a guess.
Is there anything quirky about your food choices? Do you like to select the same vegetables/protein/packets all the time or are you choosing a good variety?
Interesting that both you and your husband are reacting similarly, which might be random or might be related to the food choices.