Whats everyone's opinion?

My bf and I are normally hot and heavy in the sex dept. even when he's gone, we video chat a good bit and have done this a lil short of a year now...but it has changed to where he don't ever want to video chat or hardly even talk to me anymore! I asked him if he's losing interest and he said what makes you think that so I told him things have changed and I was just wondering why...he said he didn't know and he was sorry?!?! I'm confused is he losing interest, cheating, busy with work...I don't know and it's killing me!