My bf started given me altitude after our 4 years of relationship

Please can some one help me cause am confused.am 20 years old and I have been dating this 23 year old guy for 4 years now.for 1year we haven’t seen or chatted the all of a sudden we came back through another social media page.I was so exited cause I really love him no matter the distance..we started chatting and we spoke about how we missed each other.we we’re getting along fine when all of a sudden he started given me altitude..I doesn’t text me .but does that once in a while but he isn’t busy I felt insecured so I told him his flirting but he refused the fact..it reached a case that he stoped me from watching his status cause I always tell him his enjoying we’re ever he is so he stoped me from watching his status…he has become so reluctant to text or call me..even when I do he doesn’t reply.he doe’s that at his own time.thou his style that doesn’t cheat or have eyes for other ladies when his dating someone but I fear his cheating..please help me??advice me on what to do am so heart broken and confused 😐