My spouse is currently in rehab for what could be a very long period (several months) in a facility that is fairly far away. I need to begin the process of divorce but am not sure how this will work with them being unavailable and not close in proximity. How would this work?
Unless your spouse left for rehab with the intent to live separate and apart from you permanently, then that time will likely not count in your 1 year required separation. You could, however, begin to work with an attorney on a separation agreement.
I should have explained that we were living apart for several months before they left for rehab.