It all depends on the jurisdiction what needs to happen, you need a lawyer. If your spouse has any evidence of illegal activity you have zero leverage when it comes to your kids. So stop any further illegal activity if you are conducting any.
Do not do anything to your spouse, just get away from them.
Things are just things and can be replaced, what you really want is time with your kids so make sure that you get a custody agreement even if you do not need one right now.
Make sure that support gets handled and is reasonable and will afford your kids the lifestyle that they are accustomed to, support money is for them alimony is for the spouse make sure they understand that.
If the support money is misused you can report that, its for your kids not for handbags and shit. Get copies of any enforcement action taken, you can use those as leverage.
Do not talk bad about your ex in front of your kids, it will damage them. Even if they do it about you, one day your kids will understand and appreciate what you did for them.
Try to be a good person, be better than your spouse and don't rub it in their face it will make this go much easier. Remember that they loved you at one point even if thats gone now.
