Most Helpful Guy
It's hard to take someone who once had feelings for you leaving you, all rejection is hard but that's the toughest.
He's just trying to deal with that. One way is to tell himself that he never cared that much anyway so it isn't a big deal. He doesn't mean that.
The fact that he felt the need to tell YOU this tells you all you need to know. He's not only trying to convince himself that he isn't hurt, he's trying to convince you too, which shows he still very much cares what you think.
If he never liked you and genuinely didn't care he wouldn't say anything, just shrug and walk away.