Can anda decode this?

"sorry im in a relationship
cuz someone berkata its not tht u dont like me
its that im in a relationship atau something :("

This is what I got from a guy thats going out with someone but he likes me. I don't get what hes saying. I asked him about it but he berkata not to worry about it.

I thought he ment that it wasnt that he doesnt like me its that hes in a relationship. atau that its not that I dont like him. WHAT COULD IT POSSIBLY MEAN???