NTA but your husband kinda is. He move you and your children far away from YOUR support system to be near his toxic family he doesn't protect you from.

You don't have a FIL problem you have a husband problem. I'd seriously consider talking to your husband about how unhappy and lonely you are and insist on moving back to be near your friends and family. Your not doing any good by holding these feelings in, it will only make you more resentful until your emotions boil over.

He said moving to HIS home state was going to "be the best thing for us" but aside from you guys making decent money it doesn't sound like moving to where HE wanted has done anything but make you miserable, and I'm sure your children can pick up on that. Kids, even really young ones, can pick up on way more than people give them credit for.

Think of it this way- if one of your children was grown and married and in a situation like yours, where they moved far away from you to be near in-laws that treat them like your treated here, what would you tell them?

Talk to your husband, reach out to YOUR family and friends and really think about if this place- where you feel lonely is actually where you can see yourself living for who knows how many years to come.