My background. I married a USAF member in the UK in 94 and later on (97) we left to finish up his service at which point we were going to come back and live in England. Well after our second baby he announced that he no longer was going to go back and that I could but that he would keep the children. I was so terrified that he would that I stayed with him. He just got relocated from St Louis to Seattle and with the children's (now teens) support (he has been a grumpy difficult parent and husband) I decided to file for divorce whilst staying behind to sell the house. I told him yesterday and instead of flying off the handle as I thought he would, he gave permission for me to move back to the UK with the kids.
I am trying to not get excited as he could change his mind but my daughter (14) wants to go there to live and my son (17) might stay behind here to finish his last year of high school.
Anyway, I have to get 1 dog and three cats back which I know will cost an arm and a leg, and not to mention our essentials (photos, scrapbooks, mementos, daughters' collections).
I have wanted this all my marriage and now I finally have the chance! I do have my US citizenship so I can come back if we really hate it there right?! I know it will not be all roses but I do know that being around family again will be wonderful.
I am off to check around the forum but any advice would be great. Someone who has been there, done that.

Get it in writing and have him get it notarized. Or he could change his mind.
But good luck with the move, very exciting

Yes get it in writing and get a lawyer. Get the divorce and custody arrangements all done before you start making plans to go to the UK.

These people are actually a good resource for you as well:
http://www.militaryonesource.mil/

There is a whole section on divorce, further resources and also the option to call for information and help. It is all 100% free.

Also go to the base legal who if all this uncontested which you seem to indicate is the case, should be able to help fairly well and reduce any potential lawyer costs. Although they don't normally participate in family law the military JAG offices will help in the non contested cases e.g. drawing up the appropriate paperwork.

it may not be a priority for you which is fine but at 18 years marriage you would appear to be entitled to a portion of his future military retirement pension.

I would do all that before you get a civilian lawyer as that usually has bad consequences because frankly their motivation is not the same as yours and a military divorce always 'red flags' to a hungry lawyer as a guaranteed payday - because of your husbands salary source and his future retirement they (the lawyer) will always be able to collect. I know that might seem overly cynical and I know they are not all like that but....

Good luck.

First off, congratulations on being able to move back! I know it sounds funny to say congratulations when a divorce is involved but in your case it sounds welcome and even necessary.
Second, having gone through a divorce myself, I would suggest you get a letter from him signed and notarized immediately stating he is allowing you to take the children with you to live in the UK. That is essential. People like to change their minds and if the divorce does get at all ugly (which, trust me, it can go from decent to ugly in .1 seconds- especially is lawyers are particularly nasty) you will want/need that letter in your hands before hand.
Third, since he has stated he is allowing you to move the kids, I would recommend you aim for full custody. Getting him to agree to that may be difficult but having joint custody while trying to live in another country can be kind of sticky.

And yes, since you have your US citizenship you will be able to come back to the US should things in the UK not work out.

I absolutely agree! I had a civilian lawyer for my divorce to a US military member and that thing just dragged on and on and on. She was of the mindset (like many lawyers...) of greed and the prospect of getting more and more was too good to pass up. I finally fired her and went with another (also civilian) lawyer who got it done and dusted in a very quick time period. I was very pleased. That was also in Seattle, so if you do end up moving to Seattle (doesn't sound like you will, though?) I can give you his name.

I know I sounded like I was coming down on civilian lawyers it was not meant that way. In my experience (divorce from military member) the 'base legal offices are a great source of information and again in my experience do act with impartiality - the obvious tendency would be to think they are looking out for the active duty military member. I have found this not to be the case, but individuals always vary. To the OP especially in an uncontested situation it is likely they will assist. Also, they, military base lawyers, have the up to date knowledge of family military divorce law which sadly I have found to be very lacking in civilian lawyers (even those that profess a military divorce specialty, this where the $$ come in because they charge to educate themselves, they call it research on something which is fairly easy to understand and negotiate).

IMHO, its always 'buyer beware' with lawyers, US ones especially.

Keep it sweet, uncontested and you should be on your way.

+1. Divorce can be very tricky. I went through one 15 years ago and although it was difficult I was very lucky as we did it mostly without lawyers. No kids and we split everyting 50/50; we flipped a coin to see who got first choice of the household stuff. Even so there were tricky moments and having it all in writing keeps everyone honest.

Sounds like you had as close to a perfect divorce as one can get, glad it worked out well.

Thanks for the great advice! My lawyer is drawing up the agreement for my husband to sign. Hopefully very soon it will all be legal!

Tell him that you are doing this so that you will have no problems with the airlines when you take the kids over for a visit prior to wrapping things up with the house and pets.
A white lie perhaps but it increases the chance he will sign without changing his mind. If it is too legalistic tell the lawyer you need it redrafted into plain and simple English without any legalese. Don't be afraid to do this!
Proceed slowly, don't hit him with too many things at once for fear of spooking him into the clutches of a greedy lawyer.

You may want to have a bit of a think about university for your kids. If you are interested in a US university at a state-sponsored school (University of Washington, University of Missouri, for example) you will need to satisfy the residency requirement for "in-state" tuition, which can save you tens of thousands of dollars. Conversely, if you want to goto a UK uni, you might want to get over there sooner rather than later to start the residency clock ticking in the UK.