Am I being used?

Hello ladies! Basically I need some opinions and you are all so helpful.

My best friend used to fancy me this time last year not long after we became a thing but we had a very chuck and Blair type relationship (if you haven't seen gossip girl we were constantly playing games with each other) but I fell in love with him and he always said he didn't want a relationship which Is fair enough and he was honest to tell me but then after that he told me we couldn't even be friends we had this argument that there was literally no reason I just think he wanted me but found it too difficult I really don't know? I found it hard because I wasn't just losing a crush I was losing my best friend, this was back in June/July and until today I hadn't spoke to him since!

I started seeing another guy in August and that's when he then deleted me on social media. The new guy I was seeing ended very shortly because I wasn't over him and it wasn't fair on this guy plus this guy was an emotional blackmailer but that's another story anyway sorry to ramble on I feel like you need the whole story to understand.

But now the guy I fell in love with found out things ended with the new guy and has followed me on social media and is talking to me again- just acting like nothing happened, no apology no mention of our argument at all it's literally "hi you ok?" And we were just chatting like we would have 3 months ago?

Shall I stop messaging him back? Does he think he can just come back when he wants and thinks it's ok? Our conversation today has been platonic so I'm guessing he just wants to be friends but what would you personally do in this instance?

Thank you x