The advice thus far has been good. I will echo what was said but also point out that it's unlikely you will be able to move to the coast, or anywhere away from your stbx if you wish to have your kids in your life. Absent any proof of abuse or danger to the children, I doubt any court would allow this. Nor would a court allow your kids to be separated at such a young age. As older teens, maybe more likely.
The standard advice on this forum, which I agree with whole heartedly, is to settle custody first. Anything less than 50/50 joint legal/physical custody is unacceptable, and your stbx needs to be aware of that right out of the gate. If she will not agree to that then you cut off all communication and set for trial, which will possibly bankrupt you both. Once she sees you are serious, she will back down. Once you settle custody then you move on to assets and support.
Your stbx sounds like a miserable person and while that currently means you live in an unhappy household and have to deal with the daily grind of a loveless marriage, it could mean serious conflict and battle once you file for divorce (and yes, YOU should file). This means you need to prepare now and start to toughen up on your boundaries, which sound like you have allowed to soften or erode.
Your assets are likely to be divided in half, but you should look into whether the stock you put into your real estate qualifies for reimbursement (in CA it would).