You definitely want to hire a skilled lawyer in the area where he was arrested !
The key to avoiding a felony and prison time is providing restitution as soon as possible. You also want to show what counseling you have done to deal with your drug addiction. This gives your attorney ammunition for a successful plea bargain.
It is not unusual to get these reduced or what is called a 'rural' speeding ticket which would mean no points on your license. Please feel free to contact me about getting this worked out.
He is going to need a skilled attorney, because even if his attorney can get the new charges dropped, it is likely his probation will still be revoked.
The first thing I would recommend is to get a Temporary Protective Order against him and then get it extended in 30 days. After that, I would begin with the lawsuit.
His criminal history will be key with getting probation. Since he is in custody his attorney should get a substance abuse evaluation or mental health evaluation to see if there is an underlying issue that he needs to deal with.
If it is a first DUI you have the right to choose between a blood or breath test, a skilled lawyer should be able to get that thrown out. If they only suspect alcohol you are probably fine, they wont likely do the added test for drugs
If you don't show up to the court the court will issue an Extended Protective Order (EPO) for as long as a year. This might not bother you because you don't want to see her but it could cause problems if you are near her exchanging the children. Also it can affect your gun rights.
If you do not receive a summons within one year of the event you have nothing to worry about.
You have the right to defend yourself if you are being attacked, pursuing someone while they are leaving the scene puts you in a very dangerous situation and I do not advise it.