This is actually something I studied as an undergrad, so I can talk to it a bit, and perhaps shed some insight.

Bath Houses were indeed common during the Roman Empire in Europe, but the practice waned and ebbed as time went on somewhat. This being the time of the greatest influence of the church, the practice of bathing in a bath house was often seen as depraved. Public Bathing houses were not common because of this, and were viewed as dens of sin.

This changed after the 13th century, bath houses became increasingly more popular, until the Renaissance where they were universally accepted. It's thought that this spike in popularity in the 13th century was in part due to the Crusades and some cultural diffusion. Even before then though, people definitely bathed at home.

Soap and deodorant was common. People would scent their bath to help themselves smell better. A work by a Greek physician named Dioscorides called "Materia Medica" was common enough, it contained things like soap and deodorant recipes.

In short, people probably bathed at least once a week, probably at a bath house too once those came back into vogue. They probably also washed their faces, pits, etc. daily to freshen up. But quite frankly, this is a broad topic, and can vary widely depending upon the region of Europe.

The idea of an aversion to water and bathing too, I can offer some ideas. There was a very real aversion to bathing and water in late 18th century and early 19th century here in America. I can't say for certain if this was a thing in Europe, but people were deathly afraid of submersion of water. They also thought drinking water was a horrible idea that led to all kinds of foul ailments. A lot of these people instead would wear undershirts and shifts, changing them out when they got dirty to maintain "cleanliness" and very rarely bathe. They also drank a lot of different kinds of alcohols instead of water. So, it could be people taking these practices and applying them backwards in earlier time periods.

There's a few books you can read about the subject, and not just medieval time period.

"Clean: A History of Personal Hygiene and Purity" by Virginia Smith has an overview, but the author does make some assumptions along the way. It is however the only book I can think of that covers a lot of this in one place, and its much more broad than just medieval times.

"Foul Bodies" by Kathleen Brown talks about early American hygiene practices, its a trip, since you might be interested in the subject and history of hygiene.

"The Alcoholic Republic: An American Tradition" by WJ Rorabaugh is fun. It's old, but its still used in college courses. Goes into detail and is some insight on America's long history with alcohol, I only bring it up since I mentioned alcohol earlier.

Hope this helps.