Hello there,
When I went to the gym a few months ago I told the trainer that set up my program that I was absolutely not there to build up muscle or lose wieght. I explained to him that I have an inflammatory disease that affects my joints and told himt to treat me like a 70 year old with severe arthritis.
He set up a very gentle programme for me where all I had to do was use the machines but with NO weights. I also did some gentle exercises with half kilo (then kilo) weights in each hand.
Unfortuntately even that tiny bit of work (I went three times a week for a very gentle 20 minutes) was too much for me at the time as my disease still wasn't under control.
I think what I'm saying here is that hubby absolutely has to understand that you can not do what he will be doing and that he musn't expect that. You could set yourself back so much by doing too much.
On the other hand, if you approach thi very slowly and steadily then it could do you a lot of good and help maintain a minimum amount if fitness.
I haven't returned to the gym as I have decided to focus more on the aerobic side of things (that's my excuse anyway :lol

and I have been building up the amount of walking I do and can now do pretty brisk walks in the woods and hills around where I live. The dog prefers me getting tired that way than at the gym because at lest he has had his walk first! I also found the gym expensive as I needed a kind of subscription but ended up paying for a few months where I couldn't go as I had a very bad setback which included breathing problems.
Just some thoughts. I think it's a great idea but has to be well prepared
Katharine