Ghosted after Six Months

This has been one crappy week, and to top everything off, today I (f 42) found out that my boyfriend (m 42) of about six months has ghosted me and blocked me on everything including his phone. I have no idea why either. We weren't having any problems that I was aware of and in fact we had plans to go out of town this weekend. I just don't get it. Why do people ghost in relationships like this instead of communicating?