He reached out to me but is in a relationship?

So me and my ex boyfriend have been separated for now 2-3 months, with 1 month of full no contact on my behalf. I failed the first time with no contact and was blocked on all forms of communication due to a very nasty fight about the past, but I followed advice on this site as well as many others and posted myself improving and the new adventures I was partaking in to improve myself, and I even slowly began to get over him. I began to lose all hope that he would ever reach out, until today he actually text me. He said that a friend of his showed him a funny post I posted and he found it humorous and that he blocked me because he was just very angry at past incidents, but that all is well now. This sounds very good but while also looking at his Facebook I see the female who he got with a day after we broke up still reacts to his posts and comments. I am not sure if they are truly together but I have seen his friend, who I never got along with, post about how happy he is, that he truly likes her and how she hopes the girl “treats him right”, so I am still unsure of their relationship status. I attempted to bring up their new relationship but he resisted all attempts . I would say something like …
“I hope us talking won’t interfere with your relationship”
And he would say…
“No , it won’t. It’s all good. .” And then he would ask about my family or something.

Now to most people this relationship is an obvious rebound, but the fact that earlier into the breakup she actually reached out to me and told me to “get over him “ because he was over me, as well as the fact that he posted her and introduced her to his mother (they follow eachother on social media) bothers me. I also was getting mixed responses. Some friends were saying he’s moved on and is dealing with her seriously and some said he claimed he still missed me and that he deals with no one.

So now I am confused as of how to proceed contact with him when he and this person have been dealing with eachother for two months but have no definition of their relationship , and why he would reach out to me so friendly after a month of no contact and blocking me on every single platform, expect for a friend’s account he would use to presumably occasionally check up on me through Snapchat.

On top of that, I also made a potentially fatal mistake. I made a post that he most likely saw that implied I may be dealing with someone, it wasn’t up for very long but a few of his friends did see it. Could that possibly have anything to do with it ?