Nikki - My first instinct is to just say wait a little more (BUT be sure you''re using effective contraception in the meantime!!!). It's not uncommon for a returned spouse to still have a little sputtering contact with the OP for a while - whether they're hedging their bets, or just trying to "let them down easy", or whatever. For some it's like kicking a drug habit.
I'd give it another month - see what happens then. I wouldn't say anything to him about it now, only because you still want to know if it's happening, and if you tip him off, he might just hide it better. Over the next month the calls should start to dwindle down.
Everything else in your sitch sounds so good, I doubt this is anything more. You definitely should be setting the boundary of no contact, and it is a little worrisome that your H doesn't get that, but it's a little early to tell if he's just a sneak or if he's just doing that fairly typical "long goodbye".
My H had a couple of phone contacts with the OW after we reconciled, took him 2 months before he finally had a definitive "do not call me" talk with her. It was easier in my case because she was out of town. Must be harder with them working together.
