Dating while separated

My boyfriend has been separated since Jan and is ready to file for divorce. He is practically living at my house but has concerns that this or even publicly dating could effect his rights in court. She asked him to leave over a year ago and even filed a motion to eject after 90 days which brings us to Jan 06. They do not have assets as there is no equity in the house and they split the accounts. There is a child. We are out of state. When I read the website it appears the only issue is postseparation support or alimony which would not apply as they were both employed with comparable earnings. Someone posted on here that it is adultery and illegal even if they have been separated with a court order. Can I be sued? Can someone please give me the facts? Thanks!