Of course you feel guilty you are a mom nothing wrong with that. BUT let your logical side take over - you will still feel guilty but you will know you should feel guilty - logically you spend more time with your kids. You love your kids and it is actually good for them to be away from you sometimes.
Also, my kids' doctor pointed this out to me once -- you will be a better mom if you get away for a little while. You need and deserve your rest and time away. So realize this will actually make you a better mom in the long run when you return are well rested an have a break. The kids most likely will do well having a break from you as well.
Coming from a mom whose kids are away from her right now - they are across country with family. They are being spoiled having the time of their lives and I wish I was with them. Now I know my situation is a little different than yours, but it is good for all of us. It teaches them some independence and gives you a break.
I won't even dignify the dad comment as it is just stupid. Meant to hurt you so simply ignore it. Your kids know how devoted you are to them - kids are much smarter than people give them credit.
Enjoy your time -- you will miss the kids and feel a little guilty, but just tell your self how much you deserve it and how it will make you an even better mom than you already are.