By investing time in your marriage you are investing in them, the alone time is important and don't feel guilty you chose Disney as the place to enjoy it. 10 years is an accomplishment so don't let that be overshadowed by guilt. Can you plan something really fun for them at home while you're away? I know my kids absolutely love time with my Mother so when she comes to watch them they could care less where we go.
I also agree with planning another trip in the future that they can look forward to. Could be Disney or another place they enjoy.
Well said!