I'd need more information b/c in my world, birthdays are a BIG deal and my closest friends take off w/ me for girls trips. You're a lot nicer than me, b/c I wouldn't care if he wanted to go or not. My birthday and it's about ME.
I'd dig a little more into this bad feeling and then (b/c you're nicer than me) make some accommodations that way. Like, okay, if he's worried about a terrorist attack in London, I'd be like cool, we'll spend some time in the English country and do two days in London, middle of the week or something. If he's scared of flying, I'd have him see his doctor and get a prescription for xanax or ativan per flight (my doctor did this for me after a very turbulent flight scared me for a bit).
Don't NOT celebrate your birthday the way you want to b/c he has a "feeling." This would be the second big birthday he messed up (and I hope he made the last one up to you). Drill down on this feeling and maybe...take the trip without him. If you don't want to do a mom and Jack trip (or he doesn't want you to and you want to humor him), ask a few of your girlies to go with you. Or you could even solo travel if that's of interest to you.
Also, what have his big birthdays looked like? I'm assuming you've planned what he wanted from top to bottom. I'd bring that up, too. A lot.