I'd rope them in. Next time you do something fresh and new, ask him what he thinks, be like:
*do a little twirl, flash a smile* "What do you think of my hair? I just put in new extensions. blah blah blah"
Let them see your natural hair from time to time as well. If you act like you're embarrassed by either your natural hair, or wearing extensions, then they'll be more likely to feel weird I think. If you treat both like it's just your thing, then they won't really care.
Even if they don't like it, they won't get on you for wearing them if you're confident about it.