Why doesn't he get it?

[pll]

I like Indy's advice.

A different tack would be to bait him to get a cross bike, too. Cross improves bike handling skills (so I am told), but it also enables you t do some epic gravel rides. Here's one that has me wanting a cross bike with disc brakes (cross per se I enjoy watching, but I am not cut for it): http://www.tusharcrusher.com/

See the video from FatCyclist: http://vimeo.com/45812668 (it was his first ride with a cross bike)

[SadieKate]

I live in one of the bike-iest towns in the nation and the cool kids ride 'em all. Mtb and road bikes are hung in the garage for the winter and out come the CX bikes and nordic skis. The folks here would be hard-pressed to keep their faces straight with his attitude. Of course, you can't tell him that so I'm not much help.

[nuliajuk]

Really, it isn't actually necessary for him to "get it", he just has to respect your choice and realize that it's you that's buying it and riding it, not him.
You don't have to share every interest. My husband doesn't "get" swimming or urban cycle touring, I don't share his interest in steam trains or vintage buses. That's fine, we have enough interests in common and don't have to be joined at the hip.