You could try using the top half of a climbing tree stand. It essentially forms a loop around the stand sitter. This also may make your wife more comfortable as it gives you the feeling you have a "handrail" surrounding her in the stand.
Another approach is to use a ground blind...if you mostly zipped up and you play the wind right...it is very scentless.
You could use a monopod or bipod and rest it on the stand base. But this could get clunky if you have to spin around to point a rifle in a different direction than where you expect a deer to arrive.
I hunt with my wife as well and it can be a challenge, but the rules are she must shoot the first legal deer that comes around that she feels comfortable shooting...which usually happens early in the season. She is happy with this tradeoff as she not concerned about horn size...she likes to fill the freezer. She likes hunting together from a ground blind where I have invested in Heater Body suits and lots of hand/foot warmers and thick boots to keep her comfy. I bought a backpack to haul all the stuff out the ground blind.
Hoopi