I don't understand

So my ex and I broke up again! Well I've finally had enough of being ignored and we both agreed that things should end so just out of spite to kind of hurt him I told him I was talking to someone else anyways(really wasn't) and he said that's fine me too! I have to admit that hurt but I kind of figured anyways I told him that I'm not gonna wait for him again. fast forward to yesterday which was just a day or 2 after we ended. I was hanging with a friend that happened to be a guy. He wanted to come see my goats as they just had kids a few weeks ago. Well I took a picture and posted it and not even thinking my ex and I were still friends on all social media! Well out of the blue he messages me on Snapchat (I posted it there) and just send a pic of him not saying anything well I didn't respond I just couldn't. Well I post something else and he messaged me and said something funny so I put 😂 then he responded with 😂😂 and I leave him on open again. Well he sends another pic of him saying nothing and I again don't respond no matter how bad I wanted to I didn't. He hasn't messaged back anymore but why did he message me in the first place?