The guy honestly doesn't seem to be telling you something. Either he is confused about the idea of a relationship and being exclusive or he's holding something back. Thing is, in my mind when you date, and do all the things you are doing already, you're IN a relationship already. There's no two ways about it. Whether it's open to the two people dating others or not is the only difference. He's confused or is blowing hot air at you IMO. If he doesn't know the meaning of being exclusive, he's pretty thick to tell you the truth, and if he does differentiate, he needs to make it clear what those differences are to you so you understand and you can base your decision on that. Just the fact he's openly commitment phobic and the fact you want a relationship essentially, says to me that he probably isn't one you want to commit yourself to and you should keep looking.