I've had pretty good luck with neoprene toe warmers that go on the outside of the shoe.
https://www.rei.com/product/803548/p...hoe-toe-covers
You can get ones that go inside the shoe as well
https://www.amazon.com/Meister-Therm.../dp/B00QW10XIA
You really just need something to block the wind. Duct tape works, bu not as well at the neoprene ones. I've read posts claiming wrapping your socks in aluminum foil works great as well
But since you are dealing with a girlfriend solutions will need to be elegant.