How do I file for abandonment and adultery divorce in Oregon?

First off, you have to realize that Oregon is a "no fault" state which means that things like abandonment and adultery are not grounds for ending a marriage in this state. The main ground for obtaining a divorce (which is called a "dissolution of marriage") is that "irreconcilable differences have arisen between the parties that have led to the irremediable breakdown of their marriage." Once the petition for dissolution has been filed and served, there is no defense to this allegation and the Court will grant the dissolution. Of course, other issues like child custody, child and spousal support and division of assets and debt also have to be dealt with. If you have religeous convictions which force you to abstain from filing for divorce unless the other party has committed adultery or abandonment, you can also file for a legal separation which means that you are still married but will be separated by order of the court. When a party gets served with a petition for legal separation, they often answer with a petition for dissolution based on the ground stated above.