You are seeing a teenager/young adult at play. You may see a lot more of this behavior. MLC is all about the past and they do go back in time and revisit all areas of their past lives.
Why won't he move out? There are a number of possible reasons: 1) he's comfortable in your home; 2) he feels no pressure from you, but the minute you start pressuring him about something, he'll threaten a move, etc.; 3) it's cheaper to live at home w/"mom"; and 4) maybe the girlfriend doesn't have the proper space for him to move in.
Have you read HaWho's postings? Her h behaved like a teenager/young adult for quite some time and lived in the basement dorm room for a while until he finally moved out.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
