Why do guys dissappear?

There was this one guy we talked for like. Until one day he took me out on a date to the movies. He was such a gentlemen open the doors walked me to my door the whole nine yards he didn't even try to kiss me. A week after he came to my house we watched movies talked and talked about random things on that day we kissed. Days after we hung out again later into the day we kissed things got heated it just led to touching and i kept telling him no and he asked why and i told him cause i want it to be different and he said ok i respect that. time went on we kept getting to know each other & this one time i went to his house and things got heated again and i told him no again and he said ok but can you tell me why and i told him because i want something more than sex and he got off of me layed on his side and asked me if that whats i honestly thought of him and i told him that i didnt know and he said well if thats all i wanted i wouldve stopped talking to u after our second date, he had a point so i believed him. once again time went on i develpoed alot of feelings for the kid and one day we ended up having sex the whole time he was asking me if i was okay and comfortable and i would obviously say yes. After we had sex we talked and he got a call from his bro-in law telling him his premature born nephew was in the hospital again , the look on his face was as if he wanted to cry so i hugged him and told him that i would leave and to go see his nephew. So i left, 30 min he texted me "sorry i had to leave like that :(" & i told it was okay, he never texted back the next day he texted me "hey im sorry for not texting back the hospital wasnt gettin good reception" we carried on that convo & he start telling me how sad he was that his grandpa was dying and how much he worked etc. all of a sudden the text stopped so i figured he got busy at work the next day he didnt text me goodmorning the day after nothing so i texted him saying hello:) and no response 2 days laters i text him again and he doesnt respond its been about 3 weeks now he hasnt tried to call or text. everything was so perfect idk what happened i check his facebook and he seems fine, i just dont knoww i really gave him a chance, before him i never trusted "men". Someone just help or give me advice to keep me sane.