You do not sound selfish at all.
You sound like a caring person who wants to support your husband as best you can while you're not feeling 100% yourself.
That is courage, strength and love, not selfishness.
Going on holiday shortly may be a time that your husband finally can let some of his emotions out.
It probably wont be a completely fun holiday this time around, and letting him know that that is ok may allow him to grieve in a way that he hasn't been able to yet.
Maybe you could say to him "it's alright if this holiday isn't fun ... if you need time alone sometimes to go for a walk and be with your sadness that's ok, just let me know" ... something like that?
He might feel that he needs to be happy and strong for the holiday, especially in front of you and the children.
If you let him know it's ok if he's not happy and strong , and that it's ok for him to be sad, it may take the pressure off him and help him to feel less depressed and anxious.
Meanwhile, it's important for you to take care of yourself.
Hopefully going to your home country will mean that you might have some help with caring for your young children.
You are welcome here and we are listening.