I've never really been in that situation , but , I believe that the songs that YOU wrote are yours . You should be able to continue on with those if you want to . A good example is Gary Numan . Alot of his earlier hits like DOWN IN THE PARK , ARE FRIENDS ELECTRIC , and BOMBERS were written when he was in TUBEWAY ARMY . He has always been the writer of all of his songs , so he still performs them today . If you want to protect you're songs , copyright them . That's the best thing you can do . If not , then this other person that you are talking about could go on to make money with you're songs , if they aren't copyrighten , then you have no leg to stand on .