This was my husband...and after our first trip together he was a convert. I say don't push them and they will find something that speaks to them.
Yes to the above!
In our case, DH had been a few times before (once when he was like 7, and another time with his ex-wife and their 4 kids, where they camped in a tent and spent 2 days at
Disneyland), but he'd never really been when he could "afford" it, and he had never been with someone who actually enjoyed the parks. When I first asked him to go, we were engaged. He told me he didn't want to spend the money. I pointed out that it would be less than $500, as he would only need to pony up for his airfare, entrance ticket, and food, since I already had the hotel, and would be paying for that with or without him. Eventually, he came around, as he said, "So we could have a family vacation." On the way there, he wasn't excited about going, other than for the family time. The first morning, he couldn't have cared less about being there, other than the family time we were having. (He's big on family time!) I made sure to ask him what he wanted to do, making a point to do that first, and many times a day if we could. Yes, it meant that I couldn't get the stupid Pirates song out of my head for weeks, but that's a small price to pay.
About a week after getting home from the vacation, he told me we would be going back for our honeymoon. I told him that wasn't necessary, since he didn't like it nearly as much as I did, and he may have admitted that he liked it more than he thought he would... and now, he's made me promise he can go back every other year. Uuuummmm, yeah, okay, I guess I can allow that!
For us, the biggest things were not pushing, and letting the park do the convincing. Even if they don't care about Disney, they are willing to go to the Parks to spend time with you. Who knows--maybe the fond memories that happen will sway them to become a Disney person too!