My Korean boyfriend gone? What should I do?

So... I need some advice on this because this one is about Korean culture and dating culture.
I'm non-Korean and I met a Korean guy on a language exchange app and pretty soon after we started talking, he made it pretty clear that he was attracted to me and that he liked me so we started a relationship. Our relationship moved quite fast; after a few days of us talking (on kakao) he was saying, 'I love you' in Korean and I really came to like him and was excited by it all so I returned his 'I love you's'. I found out recently, in Korean culture, it takes quite a lot for a guy to say '사랑해요' because it's really not a common phrase.For about 2 weeks, we were talking everyday and he became quite big part of my life. One day, I saw that his Kakao picture had changed to him and this girl wearing couple t-shirts and that day he didn't message me back for the longest time. I didn't know what to think so I just left it. He message me back after hours and hours with a bundle of messages being really sorry and panicky that I might misunderstand. Then he called me (and it was quite a big deal for him to call me, like he really wanted me to know). Basically, his ex-girlfriend hacked into his Kakao and changed his picture. I'm quite cool-headed so with that, I just let it go and we carried on a nice growing relationship.After 3 weeks of us speaking, the same thing happened again out of nowhere. I woke up, his picture changed to the picture of him and his ex-girlfriend. I thought he would sort it out in a few hours like he did before but it hasn't been sorted. Now I've been through two weeks of his picture changing to different pictures of them two together all on the same day. I tried to contact him on 'Line' but it seems his account is no longer there. I also tried to contact him on the language exchange app where we first started speaking but he doesn't use that anymore.The whole situation is really strange and I can't stop thinking about it. All the sweet things we said to each other everyday, and all the plans we made for when I come to Korea in June and now it's all stopped.
I should add that because of my past, I've had so many insecurities during the relationship that he's going to leave me. I heard so many horror stories that Korean guys just leave you without a word when they please. 
What should I do? Please help.

Move on. I'm sorry to say this but he was just playing with you. He's bored with you. Be smart and don't chase someone who doesn't chase you.

sh*x.. sorry I don't have advice for you, but I do feel for you. that is so strange, the kinda stuff that makes people so insecure, worry, and demand answers, but they won't get any because he's too embarrassed to admit what he did since he knows it's bad.

so you haven't talked to him for 2 weeks? and he hasn't changed his pic yet? need more info on this one. dang... crazy stuff.

Yes, it's basically been 2 weeks since we last spoke and every few days since then, his picture has changed to different pictures of him and his ex together (all on the same day). At first I put it down to his girlfriend being in charge of his Kakao but the idea that he hasn't tried to contact me in any other way makes me just so confused about our actual "relationship".

ok, and this is long dist right? like he is in Korea and you are not?

right now from what I can tell, he has already broken up with you de facto. he just hasn't said yet, and I don't think he will. honestly I don't think you should take him back when he comes back, but I think you might. I'm pretty sure he will at least check up on you once or twice because you two did share something special and problems inevitably arise in relationships (what I'm saying is that, he might have a small argument with his ex, and when he does, he'll think of you for an hour or two), but as soon as he starts feeling better again and not needing you, he will ignore you again.

I'm pretty sure he's back with his ex.

@Dark-L : I can't tell you how to think, but I empathize with dating someone and they just leave without a word. Definitely been in your shoes. Actions speak louder than words. He's definitely back with his ex. Time to start working on moving on making sure the next guy doesn't pay for thr previous guy's mistakes.

Thanks so much for your advice you guys 

Thanks again~ >-