TIme will tell, hun, time will tell.
Document as much as you can. Keep as much as you can to e-mails instead of texts etc.,
Don't play games. Decide NOW when you will see the ILs and DHH (that stands for dickhead husband, BTW! ) Stick to that.
Rant here as much as you want. But don't do it in RL (except to those you KNOW you can trust). And be careful about the people you feel you can trust.
Namechange as much as you want to retain anonimity.
You really need to decide (and I know this is early days) - but write down all the things you had hoped for your kids. what classes would they take, where would they go to school, what would their lives be like.
No-one can give your guarentees, but that's your starting point for what maintenence / CS is relelvant. What plans had you (jointly) made for the children?
Just remember, you are married. You have rights. You have every reason to expect your kids to have the sort of life they were promised.