Things to do for non-skiers in Kitzbuhel and St. Anton Austria in late March

In St Anton, if its a nice day, buy a walkers pass and take the Galzigbahn and have lunch with your husband at one of the restaurants at the top. Or continue on the Valugabahn and lunch at the Valuga View restaurant. Or take the bus to Lech and meet him for lunch there. Then walk around town, then take the bus back to St Anton. Go sledding from the top of Gampen.

In Kitzbuehel, gamble at the Kitzbuehel Casino. Or take the train to Zell am See.

We took a day bus tour while skiing in Kitzbuhel. We found there were a number of different destinations to choose from. Or, as someone else said, you could take a train to nearby city.

If you can ride a bike I highly recommend renting one of the ski-bikes and taking a couple slopes with that. It's not skiing, but it's a lot of fun.

Kitz has a good apres-ski; there's plenty to do.

Non-skiing activities in ski areas tend to be post-ski nightlife activities. That said, Austria has a lot of winter walking tracks where snow is groomed (packed) for hiking.
https://www.kitzbueheler-alpen.com/en/winter/winter-hiking-snowshoe-trails.html

Explore the sbnow-covered Kitzbüheler Alpen in Tyrol on a winter hike.
The cleared trails for winter hiking lead through an idyllic winter
landscape. Enjoy the picturesque views of the snow-covered Kitzbüheler
Alpen. Enjoyment is never far off when winter hiking, as all winter
hiking trails lead past rest stops and inns.

https://www.j2ski.com/ski_resorts/Austria/Kitzbuhel.html

Kitzbühel Aprés Ski Kitzbühel is known for its lively and often
sophisticated nightlife centred on the many restaurants, 40 or so bars
and four discothèques. Especially popular bars include the Londoner on
Franz Reisch Strasse, the Goldene Gams on Vorderstadt and Flannigans
on Jochbergerstrasse. Warming drinks on offer include 'Jagertee' (tea
with rum or schnaps) and Glühwein. The Casino is open daily from 7pm
with live music in the lobby from 9pm. There is also a cinema and
other popular evening activities include bowling, tobogganing and
sleigh rides. The ice rink is open 13.30 - 16.00 everyday, as well as
from 20.00 - 22.00 on Fridays and 10.00 - 12.30 on Sundays.

For me, there are few things as rewarding as a nice hike in nature.

I'm not familiar with St Anton but visited Feldkirch many years ago, which I remember liking. If you have a car, Stift Stams is close by. Innsbruck is fairly close if you have the time, as is Mittenwald in Bavaria.

Near to Kitzbuhel I liked Zell am See (not sure about the time of the year). Kufstein, with its old town and castle, is well worth a visit.

Consider taking a cross country ski lesson: https://www.kitzbueheler-alpen.com/en/winter/cross-country-skiing-schools.html
While it is not true that if you can walk you can do XC skiing, gliding across the snow on cross country skis can more enjoyable than hiking over snow.

When we lived in Munich and had visitors in the winter one thing that has always been a hit with non-skiers (and skiers) is sledding.

https://www.innsbruck.info/en/sport/winter/tobogganing.html
https://www.kitzski.at/en/skiarea-tyrol/skitouring/tobogganing-in-kirchberg-sledding-fun-on-the-gaisberg.html

Typically you can take a lift up the mountain (sometime you hike up), stop at a hut for some coffee/cake, sled down and do it again.

DJ