If you didn't take the lead and plan an observance, would he be disappointed or wonder what was up, or would it even cross his mind?   Have you ever told him that it'd be nice if he did the planning once in a while?  My own husband just isn't much on those kinds of events, so if I want a dinner date or some sort of celebration, I'd better plan it.  To me, it comes under the "pick your battles" heading.  If I felt stronger about it, I might push the issue, but as it is, it's the status quo we've established.