You need to read the post “Final Definition of Adultery” on the Lawyer Will Respond board. My best understanding is that sexual relations before your final divorce is cheating. During my first marriage where my wife was only interested in her boyfriend, I started dating after a month. During this divorce, I fear my spouse would try to have me arrested for adultery, so I’ve been a good boy for 13 (long, eternal, forever) months now. Personally, unless you are divorcing a really hateful person, and especially if he is seeing someone, I don’t think you would have any problems. I would wait a couple of months had past since separation.