I've been lied to and dumped

Hello everyone! I thought I would post this also here, and see if someone can give me some good advice.

I need to take this load off of my head. I'm feeling terrible, actually I've been feeling like this for a moment now. I live in a foreign country, speak a different language, living a different culture. And all this makes everything a bit harder when we're feeling sad.

I've just finished an awful long-distance relationship. I trully wish I never met this person in my life. He showed himself so caring at the beginning to finish being a coward and a liar. We were friends just before our relationship, and I thought this person was so nice. When I saw the possibility to have something more with him I accepted, even though I knew distance makes everything complicated. And because we were friends before, I knew a lot about his ex girlfriend(who also lives in another country), and how he missed her, how he dreamed about being with her again. So when the relationship started, all that information was also creating a barrier between us. I felt threatened all the time thinking this girl would come back and he would leave me.

She didn't came back. Actually she never left. I found out I was just a rebound. I discovered he talked to her behind my back, and the excuse was that he wouldn't tell it to me because it would hurt me to know that, but that she's only his friend. The pain was deep for me, because I was feeling insecure, and this just confirmed he could actually lie to me...

After a month of no-contact, we we started communicating again, and we even met in person. We spent a lovely weekend together. Until he had a jealousy attack and left me totally alone in a foreign country... After that he said he was sorry, he got too mad because he felt he would lose me. I knew then he also had some strong insecurity issues. This situation led us to a conversation about our problems. I tried to bring up the topic of his ex, but he was avoidant. He said I payed more attention to her than he did, that he cared for me and not for her, that she's just a friend. I tried to understand, at that moment I felt my insecurities were actually irrational. So I only asked him to be honest and never hide things about her again, that way it would be easier for me to leave that issue behind. He did promise he wouldn't do that again.

But just a week after, I got a message from him that wasn't meant for me. It was for her. He was talking about a concert: they were organizing to go together there (to her country)... I tried to talk to him again, but he would get angry at everything I said (if I sweared, if I was too angry, I thought he was trying to find flaws in me to justify his own ones). We exchanged some emails ever since, and he would also leave an "open door". In the last one, I told him that I realised he lied moore than I thought he did, just by re-reading our chats and emails. He said things like "I don't want to see her", "i wouldn't travel to her country", and of course "I won't hide things to you anymore". He never answered this email.

You can't imagine the state I'm in now. I cry every single day. I feel like rubbish, like a pice of s****. This confirmed my other insecurities: I'm worthless, totally worthless. I have very dark thoughts ever since, and I have nobody here to help me. Please, I need some help, some words to understand life is worth.