I'm new to getting back out there, but have manners changed that much from back in my day?
Not much. It's pretty much the same, as far as manners are concerned.
we began walking up to the theatre and he suddenly veered off way over to one side, still walking in the same direction but quite far away from me. All the other couples I see in public walk together. I took a shower and brushed my teeth before the date.
Far far off? If he went way out, as others have noted, maybe he had some bodily functions going on. If a guy is walking too far ahead of you, he may need to pee real bad. This situation has nothing to do with generational differences - lol. Even people who aren't on a date aren't going to walk Way outside the other person.