I've totally had that problem before!!
There's lots of neat stuff to do there, but I think the main objective is staying away from the little kids who are there. I like families and babies very much, but if you have a BF who's not keen on the MK to begin with, kids may make it worse.
So, what I would do is this:
1) Know what rides you are going to do and when. EX: You won't be riding Dumbo, natch. BUT---The Astro Rockets are actually cooler and scarier that you think. So ride that early in the morning (it tends to get a long wait). Try Aladdin's carpet too - watch the camels. Maybe go over the attractions with him, to see which appeal to him.
2) Similar to what I said regarding Astro Orbitor, don't discount some attractions that seem lame. Like Tom Sawyer's island - it can be really cool and a VERY nice place to get away from the screaming kids.
3) Take advantage of every single FASTPASS you can get!!!!! It will save you time and headaches.
4) Although the MK doesn't serve alchohol, you can always hop a monorail and get a drink at any of the lounges. ("Get looped on the Loop!") My fav: get a drink at the Tambu Lounge at the Polynesian and take it out to the beach and watch the fireworks from there. Very romantic!
5) Consider a "Keys to the Kingdom" tour? It's a little $$, but your BF might find it neat. You get to see computers and AudioAnimatronics!
6) Eat at off times to avoid the families. For fast food, the BF might like Pecos or Cosmics (both have great "fixin's bars") Or, if you want sit-down, Tony's or Plaza Resturant are both great.
7) Really, take your time and just relax. Who knows, he may surprise you and want character autographs, mouseears and the whole nine yards!
Good luck!!!