My boy friend lives in germany?

my bf lives in germany and we talk on the phone but really never see each other he is doing all these changes and i think hes seeing another man!!! wt should i do i don't want to out of the blue confront him until i know for sure becuz he mite lie to me or tell me the truth and i don't believe him long distance relationship i went out there last week and its like he went out without every nite i was there and this man chuck always called in the middle of the nite and in the early morn.he even didn't want us 2 sleep together he all of a sudden wants to be selibite yeah ite boi been a freak since i met him