I feel you so bad right now! My husband did not grow up in a family that did any type of big vacations. A couple days at a lake 20 minutes from home was the extent of it. He argues that they were happy and fulfilled and didn't need much else. As a result, he has developed this odd guilt over taking vacations. We have never gone anywhere (besides our honeymoon), before our kids were born or after, where he has not gone into full panic and guilt mode over it.
I had to drag him kicking and screaming on our first trip to Disney. We can technically "afford" it, but he always comes up with valid reasons for where else that money could be allocated- i.e. saving for college (we have 5 kids!), paying more towards our mortgage, finishing our basement, and the list goes on and on. He is right-- there are MUCH more practical ways we could spend our money than on a Disney vacation. We have been a total of 3 times and he wrestles with this guilt each time we go. However, he is the HAPPIEST member of our family when we get there. I think this is what makes him keep going back. He would never go without someone like me to push him there, but he is always glad we went. Rarely, does he mention the expense when we get home and are left with just the credit card bill. Because we are also left with AMAZING memories to last a lifetime.
Our kids may not remember all these trips, but I will. I will cherish them in my old age. My dad was sick my whole adult life and died when I was 30 after a long battle with Parkinson's. My mom is suffering from elder depression and other physical ailments since his passing. She lives with us, so I am exposed firsthand each day to the difficulties and heart-wrenching reality of aging and I will not feel guilty for experiencing enjoyable vacation time with my family while we are all still young and healthy. These are good years, and I fully intend on taking advantage of them. YOLO!!!!
Some things that have helped with this are: like the poster above, we ALWAYS stay offsite. We have a lot of kids, and we need in-unit laundry and space. We almost stayed at the Campground Cabins this past trip but when a deal came up for Bonnet Creek that was $150/night less than the cabin, I could not justify it. Where you only have two kids, you could stay at a value resort on the cheap. I would if it was just four of us. We also grocery shop and prepare most of our own food and rarely do ADR. If you stay in a hotel with no kitchen you will need to do the meal plan so maybe budget for that. We drive from New England to save on transportation, and we spend very little money on "stuff" in the park. I usually buy just one ornament for our Christmas tree, or I let my girls get inexpensive birthstone Mickey earrings. We buy our Disney merchandise to wear to the park outside of the Disney parks. We always buy tickets from a reputable discount vendor. And I search for as many deals as I can. Maybe if you tell him you are willing to compromise on some stuff, or do your research on how your family can save, he can be convinced. Good luck and keep us posted!