See the reply by tomkinstinch. It is likely that the combination of gases produced by your skin's microbiome are more attractive to mosquitoes than that of your wife's.

This seems more probable than increased amounts of CO2 floating around your feet and ankles, especially if you are laying next to you wife where the aggregate CO2 from both of you breathing will be distributed fairly evenly between you.

A quote from tomkinistinch's linked article: "...washing the feet with a bactericidal soap significantly alters the selection of biting sites...".

I wish we were at a point technologically where it would be simple(and cheap) for a person to detect and catalog things like VOCs that skin bacteria produce, or quantities of bacteria on the skin to determine how they correlate with something like mosquito attraction.

It would be pretty great to be able to say definitively that x bacteria concentrations on your skin are attracting mosquitoes to you, rather than simply conceding "mosquitoes love to bite me".