long distance advice

I've been speaking to someone since July 2016, it was pretty intense. I flew to Barbados to meet him in Jan. We had a great time, hung out for three weeks. Then met again in March for a month. Now, he's gone silent and I don't hear from him as much. I live in the U.K. There's where I am now. He's in the states. I'm not sure what to make of this. It was all great and then silent.