My husband and I moved back from London to Ireland when our son was a baby for pretty much the same family reasons you did, although I consider it much easier raising kids here. From my perspective though, job opportunities are much less, the weather sucks big time and I am back among the narrow-minded people I couldnt wait to escape 20+ years ago.
On balance though, it has been a positive move. My children see all their family regularly, my parents who are now elderly are close by and I have rekindled friendships with a couple of people I went to college with who arent too far away, as well as being able to find some like-minded people whose kids go to school with mine.
Try not to be negative about it and think about it in terms of overall quality of life for all your family, which is presumably what your husband is doing in agreeing to the move.
ADD I have to ask why dont you have much of a life where you are? Through your childrens school and work you must meet people. Since we moved back, we have both become active in community work, which has not only widened our social circle, but given us work opportunities. YOU have to put yourself out there to make friends, get outside your comfort zone. By moving back home, arent you accepting that you failed to create a life for yourselves independently in a way?
Are you SURE that location is truly the source of your depression? Its normal when we feel low to want the security and comfort of our family, but if you are so low that you cry, there's more to it than that. There's a good chance that you will incur the upheaval and expense of moving home, only to find that your depression has tagged along for the journey. Depression comes from within - you cant run away from it, you have to face it head on.