I won't go to Biergarten alone because so many object to sharing the table with a solo. At Teppan Edo they don't seem to mind as much. Have also been to Biergarten with a group when a couple objected to being seated with us. Apparently they thought they would get their own table. They also didn't like that we were drinking beer. They wanted a teatotaling table. They were not moved, they had to sit with us. We ordered more beer (would have done that whether they were present or not) and they looked like they had been seated with the Charles Manson family.
Short answer for the OP - if your husband is dead set against having tablemates, then there isn't a huge chance that his requirements will be taken into account by Biergarten. It might be a possibility if you arrive early, if you tell the person doing the seating that your party cannot accept a shared table, and are willing to wait for a smaller table (I understand there are some but not many) - but you can't count on it.