Now retired, my husband wants us to travel - I will miss Grandchildren!

I understand your feelings, Minalta, but agree with the other posters too.
Why not start discussing with your DH when the trip might be, where you will go etc to rekindle your interest in it.

Don't miss this opportunity Minalta, it's only a few months and will be such a wonderful experience. There are so many ways to keep in touch with your family now you will miss very little.
You are lucky to be able to do this as many people are restricted by health or financial issues so enjoy the time with your husband.

Go with your husband on this adventure. Your daughter will cope. You will be able to communicate daily on Skype or Facetime. And you will have wonderful stories to tell your grandchildren.
You only live once.

Meant to add, what about your feelings for him? What about honouring his feelings?

Should be texts from DD of course.

I think you are being unreasonable as well, minalta. Your husband has feelings too and he's only wanting to do something you've both always dreamed of doing. 3-4 months is not all that long. I'm also sure your husband loves his grandchildren as much as you do.

I know exactly how you feel Minalta except that my DH feels it even more strongly than I do.A fortnight is the most we are happy to be away from the eldest grandchildren because we see them so frequently.However if your DH feels differently you will have to compromise and it will be nice to receive texts etc.from DH telling you what the children are up to while you are away.It will not be so bad when you are away filling your days with interesting experiences.But I do understand your feelings.

Minalta why do you feel guility about leaving you daughter to cope ? they are her children, did she and her husband consult you before they had the children regarding the life you were to give up ? You say they need date nights, what about your Husband ? is he just forgotten ?
Sorry to be tough but your Daughter is a big lady now not a child playing with dolls.
Why not agree with your husband and defer the trip until after the little ones first birthday ? This is a trip you say you have always dreamed of, yet now your long held dream is dropped.
Put yourself in your DH shoes for a moment, you say you are heart broken just how do you think he feels ? pushed out and unimportant i would say.
Sorry to be harsh but you need to live your life for you not your daughter.I had a friend who put her life on hold for her daughter and DGC, she done the childcare even whilst recovering from a transplant, her husband wanted them to move as he thought she was being a doormat, she said she could never leave them, i asked her what she would do if her daughter moved away and she said it would never happen as they were so close, a few moths later the daughter moved 120 miles away and my friend was left with a empty life and irate husband

My older son lives in America so I see my GC there once a year, if I'm lucky. My other GC lives over 500 miles away so three months is the norm to me for seeing him. Think how much you'll have to tell your GC when they're older about your travels!