[pushkins]

I'm not sure your husband is going to like the news but the only thing that is going to work long term is to remove the existing wallpaper and either re wallpaper of refinish the walls in some way.
Once the paper starts to come away from the wall there is little you can do to save it. Most fixes are "quick fixes" and last short term.
Your home is 100 years old so the walls are old plaster, removing the wallpaper will most likely do some damage to the walls (depending on how well the home as been kept over the last 100 years)
Many times what is actually happening is that the plaster is separating from the lathe and causing the wall paper to bulge outward. It's not uncommon in this age of home.
Sorry to your hubby there might be a few weekends of work ahead of him.