Originally Posted by River
Even though he knew that it was "officially" okay for him to see others while in a relationship with you, he probably had fear of telling the two of you because of his own monogamistic conditioning / programming.
I think River pretty much hits the nail on the head here.
We are still living in a culture where knowledge & experience (especially experience) in these alternatives is sorely lacking. Consequently, how they proceed is often some distance from where they would in an ideal world/culture.
Myself, I simply wouldn't stress over this at all ! It seems all his intentions are in order and he did the best he could with the limited experience he has. Make allowances for this - not just with him but yourself (all). You can be sure other issues will surface over time if you continue down the path and this is a great opportunity to get a handle around the fact that this is all new and NOT easy. Stay together on it and don't overemphasize 'mistakes' that happen via the learning process. Just make sure you DO learn