How to spice up a boring marriage?

I mean, sure, we still love each other. But lately things have become... stale? Routine? No animosity or hostility at all, just simply... I don't feel excitement or fun anymore. We do have sex pretty regularly, about once a week (which we're both very comfortable with). I've just had this strange disconnected feeling for the past few months now... We used to hold hands everywhere we went, hug and do quick pecks on the lips several times a day every day up until the first 3 years of marriage. Now, when we go walking in public or go places, I try to link arms like we always did but he doesn't reciprocate. He doesn't REJECT, yet he doesn't initiate anything either.

We are only approaching our 4 year anniversary and it feels like we're already in that "7 year itch" or whatever it's called. I feel foolish and embarrassed about being the one in the relationship who seems to be trying to keep up our old ways (small physical touches, meaningful conversation, etc). Anyway... just wondering how other couples handle this weird disconnected phase.