Help, I need ADVICE!

Before I go into what it is I want advice about I would like to give a little back story.

Over 10yrs ago I worked in retail with this guy who I will call “frank”. So while working with frank we never really spoke, he used to always smile, wink or grab my hand and tell me how beautiful I was. At this time I was in an abusive relationship so my head was more focused on getting out of that relationship and not really think about frank. Fast forward to 2011. That was when we became fb friends. Once again never really spoke to each other, we would like each other pictures on occasion. In 2012 I moved to another state, even though we never really spoke, it was something about him that drew my interest. So now we are in 2015 I took a leap and decided that I wanted to initiate conversation. We talked as friends off and on since 2015, now that I was getting to know this mysterious fellow I was more into him. He’s really sweet, very intelligent and is very gorgeous. He’s compassionate, basically everything you would want in a man. But we never expressed any feelings that we have towards each other until recently. He asked me to marry him and have his 5 children. I laughed because I thought it was a joke but he was serious. Keep in mind I still live out of state. Anyway, I plan on moving back to the state we are from but for other reasons. I have a daughter already and our first argument was when he got a little frustrated when I said I didn’t want him to meet my daughter right away. He then explained why he was frustrated about it. But now I feel as though he isn’t into me anymore because now he goes all day or sometimes days without talking to me but before he would constantly contact me. He’s a cancer I heard they are wishy washy but I need to know if I should take him serious or should I just leave him alone, I mean I really like him but idk. Like can someone please tell me if they are dating a cancer and how is their cancer with them and what to expect or should I just move on. Sorry if I’m all over the place but I’m typing this as my mind is all over the place.