Why does he keep me around if he doesn’t want a relationship?
What you are probably experiencing is called “being led on”. The person you are with has you as his “backup”. A person to fall back on when he has a falling out with his girlfriend. Or you are just a person he wants to have casual sex with on the side.
If your situation is a cause for concern, it probably means that you should get away from that person, sooner rather than later.