If you file for a dissolution of marriage (divorce) in Oregon, you have to allege that "irreconcilable differences" have arisen in your relationship with your husband that have led to the irremediable breakdown of the marriage. Once that allegation has been made in a petition for dissolution filed in the county where you have lived for the last six months, your marriage will be dissolved and your husband cannot contest that result. Other issues the dissolution proceeding must address is custody of the children (you will get sole custody for sure if he has been convicted of a felony sex crime), parenting time for the non-custodial parent (none if he is still in prison or under supervision), child support (you probably will not get any if he is incarcerated) and division of your property and debts (the law requires a "fair and equitable division"). While the courts do have forms that you could fill out and file, you should at least talk with a local attorney to get a better idea of what will happen given your specific circumstances.
Answered on Feb 25th, 2014 at 4:17 AM