I can't believe he just did this

So I got out of an abusive relationship 1.5 years ago and I was talking to my current boyfriend about how I'm so happy that I'm going to back to myself and how I'm finally feeling confident about myself (which is a big accomplishment) I told him that I no longer feel intimidated by other girls & my jealousy is gone. He said he was happy for me.. so what does he do? He goes out to a party with one of his girl friends and has been taking pictures with her all night (posting them all over snapchat) & they're now hanging out in his room.. which he made sure to include in one of his many pictures. He also has stopped texting me back.. he's never done this to me before.. should I be worried? Do you think he's just testing me? I don't even know what to think