I am new to the forum but when I am part of a forum I generally do not like to bore people with long responses so if this gets long I apologize.
I am getting divorced. And while Disney is not the reason, the reason is similar to what you are talking about. My wife went to Disney several times during her childhood. The first time I went was our honeymoon. She talked me into it. I went and I LOVED it. We stayed at the Floridian so that was part of it but I just fell in love. We went back as a couple 2 more times, the last being with our oldest child. (On a side note, I fell in love with it even more after reading several biographies on Walt. Just seeing what he and Roy went through to start this company inspires me and makes me appreciate it even more)
As time went on, I always wanted to go back and she would make up reasons not to. Well, I have been a stay-at-home dad for the last 5 years. I went by myself because she wouldn't go. I wanted the whole family to go but she said no. I was burnt out being in the house all the time, running errands, etc... So, I just went for a long weekend 2 times with the last trip being in August 2013. It was around that trip that she started insulting me, saying it was weird to go by myself, she had told one of her friends I was going and then passed on the info that she and her husband thought I was weird for going without the kids too, etc... I'm sure a lot of people think it was weird but I offered to go with the kids and leave her home so she could have time to herself. She thinks it is a lot of work (we have 4 kids) so as another attempt to compromise I said we could go to the parks for only 4 days of the 7 we were going and hang at the pool the other days, etc... She said no to all my suggestions.
It wasn't just this issue that caused our problems, obviously. But, as it has been said earlier in the thread, if she is laughing at your suggestion to go that is a sign of disrespect. That is a bigger problem in any relationship, regardless of the topic. Someone else brought up an excellent issue though. If you get married will she like you spending joint money on Disney trips if she doesn't like it? The only reason I was able to go was because I had always gotten Disney gift cards on birthday's and holiday's so it cost me nothing either time I went. In fact, she and her "friends" asked why I didn't go around where I live just to get a break. On top of loving it at Disney, it cost me no real money because of the gift cards and we had a credit on JetBlue that would go to waste if I didn't use it. To stay around my house would cost me much more just for the hotel.
In your situation it could be the opposite. If you got married and had kids maybe she would end up loving it when she sees how happy it makes the kids. Who knows.
I can tell you this though, I am 40 yrs old. If I never end up meeting someone else I am fine going with just me and my kids. If I do meet someone else, she will have to like Disney. I truly enjoy it and I don't ever want to be told I am weird for wanting to go or that Disney isn't important (which she has said numerous times in the last couple of years)
One last piece of info: She hasn't wanted to go anywhere else on vacation either. I tried that compromise as well, so it's not that I am just some selfish Disney fanatic.
Just take a look at other apects of the relationship and see if you guys are disrespecting each other in other areas as well. I'm guessing it isn't just Disney. If you truly love and respect someone you want them to be happy. Laughing at someone or making them feel stupid for something they love is not respect. I mean its not like I was a drug addict and she made me feel guilty because it was affecting the kids or something. It's DISNEY!