What is up with me? 5 STARS BEST ANSWER?

I have a boyfriend and I like him a lot. I would do anything for him, best thing that's ever happened to me, yada yada yada. Get it? Whole 9 yards. Okay, I know its not very convincing but I have the weirdest feeling that hes cheating. Hes acting really weird and its a long distance relationship so anything can happen but he "promised" he wouldn't "hurt" me. He is normally really honest but I have asked him and he said he wouldn't do that to me. I really wasn't convinced. When I was texting him (he normally texts back fast) he was texting slow and responding with things we weren't even talking about. When we talk on the phone hes always boring. Maybe the relationship is dead but I feel like threess another girl. Maybe I'm paranoid but I've never had this weird feeling.