Panda, if one of your girlfriends told you the things below and asked you what you thought about her moving a long distance to be with him, what do you think you would tell her?
"Two months before I move, he started to act weird, always online everywhere but saying he's not talking to me because he's busy playing online video games"
"he said he asked a girl out. Then he said he wants us to get back together with me but he needs time."
"I ... found out nasty stuff like girls sending him half-naked pictures etc."
"and he's either very nice to me, or really mean, saying I crushed his heart when I left him and it takes time to heal."
"after I accidently talked to one of those girls (and told her "I'm his girlfriend") he somehow changed them an hour later (is there internet in fishing cabins?) and turned off his phone so I have no way to reach him right now."
"he keeps treating me like a door rug"
"He used to be the sweet person I fell in love with,"
"he keeps saying he wants to be with me, I see no proof but other evidences that he might be/was cheating."
He should be excited and telling you how much he can't wait till he sees you and holds you and kisses you and ... well, you know the rest. Instead, he's acting like it doesn't make any difference whether you come or not. This is a bad sign and I'm afraid that if you go you'll find out he doesn't want you there and this will break your heart even worse and cost you lots of money also. I hope I'm wrong but it sounds like now that he's got you he isn't interested any more.