Telling another person how they ought to manage their emotions can be pretty useless. For example, I can appreciate the logic in another person telling me I should keep my house tidy when I'm super-busy or under stress, because having organized surroundings will help me feel like things are under control. But I'm not going to become a completely different person because I heard some good advice. When my life gets crazy enough, my surroundings will eventually become cluttered. That's just how I am, wise or not.
In the same vein, it may be useless to advise you - or your husband - to base your happiness less on having what you want; and more on knowing of yourselves that you will sacrifice your own wants, for the sake of your kids' needs. Maybe - even if you agree with that ideal - one or both of you just aren't wired to live in circumstances you don't like, without getting so mired in depression that it might actually be better for your kids if you lived far away from them, but weren't depressed. No one knows better than you and your husband, how the two of you are wired. And there's no rule book with definitive "rights" and "wrongs" about decisions like this. (Although GOD, I wish there were!)
The essential difficulty is this:
> A person in your situation might decide to move out of state because you realize that your husband is incapable of pulling himself out of his depression, and it's so bad that he's damaging his kids. People aren't perfectly logical robots. We have to do the best with ourselves - and each other - that we can. So, this might be the wisest choice you could make, under imperfect circumstances.
> But a person in your situation might also seize on the idea that "my husband will be a better father if he's happy, and he can't be happy here", as the easiest way out. If you convince yourselves that moving away would be for the kids' sake, you and/or your husband might make less effort to embrace your current circumstances.
So if you do move, think long and hard and make sure it's for the first reason, not the second.
Just from your brief post (I read the unedited version), it sounds like:
1- You and your husband originally decided that moving near his kids was best for them and justified the financial and other sacrifices in your lives. You're rethinking that now - in part, or mainly - because you have a new baby coming. It's natural to want to give him/her a life based on everything you think is best and most wonderful...not a life shaped by his/her dad's ex-wife's choice to return to their hometown; and your concession to follow her, to be near the older kids.
The older kids' need for their dad to be part of their daily life has not changed.
It's unavoidable that every child's life will be shaped by their parents' circumstances. Even if you lived in your favorite place in the world, there would still be things you'd fantasize about providing for your child, but weren't in a position to do. Having loving parents - whatever your circumstances - is so vastly more important than having the ideal circumstances. And growing up near his/her older sisters could arguably be a much greater blessing for your child, than growing up in your favorite city - and only seeing his/her sisters on breaks from school; and being (in some ways) the reason their father moved away.
2- You and your husband hoped to resume his old connections, but have them be better; his family might grow more accepting of you; his old friends might embrace you; his ex-wife might become less hostile and co-parent more nicely.
His family will almost undoubtedly warm up, once your baby is born. Babies have that effect on stubborn family members.
But you can never go home again, as they say. Rather than approaching it as a return to his hometown, it would be better to look at it as you and he having moved to a new place together and having to find things you like to do - and people you like to do them with - just as you would, if, say, you moved to Hong Kong. It's just that, on occasion, you run into people your husband knew in high school, who happen to have "relocated to Hong Kong", too. There shouldn't be an expectation that he resume the same relationships with them, that he had in high school.
My last three pieces of advice in this long post (sorry!!):
- If I recall correctly that your step-daughters are 6 and 8, they'll finish high school in approx. 12 years. That's not the rest of your life. After that, you could move with your younger one, who could attend middle and high school wherever you'd rather live.
- When my step-son was 7, his mother decided it would be better for him if she were happier, and she'd be happier in California. My husband traveled there to visit every month. Nevertheless, he was a special event in his son's life, not part of the day-to-day.
- Now we have a 5-year-old. If my husband were still making those monthly visits, it would be very disruptive to our little one's life. Not to mention, the two brothers would have a relationship more like cousins who spend part of the summers together at Grandma's, rather than siblings.
- My step-son came back here, to live with us, when he was 8 (long story). Now he's 14 and a freshman in high school. His life (in his mind) is starting to revolve around his friends. He loves his mother, but resents that visiting her takes him away from what all his friends are doing on school breaks. It interferes with his chance to have summer jobs. His summer visits with her get shortened, by summer school or summer training for his sports team. It is harder and harder for his mother to be any meaningful part of his life...and at a time when kids really need the guidance of both parents, as they navigate all the risks and emotional ups-and-downs of teen life. Sooner than you realize, long-distance parenting of your oldest step-daughter, in particular, will be a whole different ballgame than it used to be. (And even as it used to be, you and your husband still decided it was best to move closer to her.)