Call his bluff. Tell him fine with you if you don't go and he'll probably be back to persuading you it's good for you to go! Sounds like he's worried you'll change your mind once you're there and that will impact on his career and ability to support the family.
I've been a serial expat for 16 years. First move my DH moved countries for me, next move was because we both were offered jobs in another country at same time and last move was his job. Each one has worked out well for us and made us appreciate the UK more, I love going home to visit family and friends but quality of life, depending on where you end up can be higher elsewhere so you can hopefully have best of both worlds.
Are you reasonably outgoing? If you're comfortable making new friends, a stint overseas can be fantastic. Most people I know have made expat life work for them positively.
Be prepared to commit for at least 2 years before making any decisions about whether to stay or leave. 2 years will go by faster than you think and it usually takes that long to really find your feet and work out how comfortable you are somewhere.
Travlledtheworld is right, it can be tough on a relationship and will be lonely for you to begin with. He'll make friends through work, you'll have to work at making friends which might feel a little unnatural to begin with. But in my experience some of the best friends I've made have been my expat friends. I'm still close to the first friends I made 16 years ago even though we haven't lived in the same country now for 12 years and are 12 hour flights apart.
As your children get older and start school, it will be easier to make friends through school etc.
I'm biased, I'd say give it a bash but it does need to be a mutual decision, recognising that it will be tough at times. Both of you might have doubts at different times about whether you're doing the right thing but you have to support each other and not put either one under pressure to make the decision and carry the can if it doesn't work out.