Good for you, tg!
You know what occurs to me, is that early on, he might have felt like your attending the same meeting at the same time made him feel "checked up on"--i.e., like your being there was to make sure HE was being there. That, of course, is HIS problem, not yours, but I kinda understand how it might feel that way.
In the beginning, that is.
So I don't know that it was a huge "control" issue, it might have just been one of those early recovery mental hangups that we get--fear of what others are doing, or saying, or thinking about us.
Just speculating, and imagining how I might have felt in that situation.
I'm glad you went, and I think it was the right thing for you to do. If it makes him feel "weird" still, that is something he needs to get over for his own sake. You keep doing what you need to do.