L.B.
I think I have a different take on this than most - my son was without me at 10 days old when I had to have emergency post C-section surgery. So he went to stay with my Aunt, who lives an hour away. Yes, at 10 days old he really didn't have a clue. But this initial time with my Aunt and Uncle led to extended stays for him, with them, as he reached toddler age. He would gladly pack his bag and go to MawMaws for up to 2 weeks.
When he was about 6, I started traveling about every other month, over a night or two for work. He had a series of sitters that he stayed with, we talked on the phone every night - it just was not a big deal for either of us.
Don't get me wrong, I missed him when he was with others, or I was out of town, but I knew that he was well taken care of and he was only a phone call away.
So go on the trip with your hubby. Your son will be well taken care of and it will be a nice time for him to bond with his grandparents. Healthy, happy parents are the best thing for him.
Good Luck and God Bless