Why do guys do this ?

I met a guy and we started talking quite a bit. During the process he flirted a lot and made it seem like he was super interested but I told him I'm not very trusting because of my past relationships. However, he would always say that I would have his child and then later on down the line said that I was going to be his wife. I started to like him, but I think he got scared and kind of distanced himself. He told me he didn't want a relationship right now because his main focus was to move up in his job But he would always say you're pretty as hell though. I had no problem with being friends because I just got out a crazy long relationship myself. But now he's kind of stopped all communication. He will still like my post on Facebook and watch all my snapchats but hasnt texted me. He's always said he doesn't really make the first move which I'm used to men making the first move. But why do guys do this? They seem all interested, say crazy stuff like marriage and then ghost you ?! Lol.