Long distance and rebounds... would love advice from men and women! Sry SO LONG!

My ex broke up with me 2 months ago, at that time I moved home and we were 800 miles apart for the last 2 months. I did NC, but he always managed to get in contact with me in some way or another. He was super depressed for a few weeks, then he picked up a rebound girl during this time. After a month of limited contact, we decided to meet up and I went to see him. We fell into old patterns and things first started out in arguments (because I found out about the rebound) and him getting mad at bars when a guy would hit on me. Well, towards the end of my visit we managed to get back to a comfortable place, but he said he was still confused and could not be with me.

I went home, super sad, and decided complete NC this time, called him, told him the break up was fine and told him he did not deserve me right now. A week went by, and he incessantly called and texted me, being very desperate to talk to him. He went on a boys weekend to get his mind off of things (rebound still in picture). He called me, and I picked up and finally asked what did he want. He said he wants to try to work on things with me slowly by stay single and continue to talk to other people so we can be sure we are right for each other. I was upset about the circumstances, and spent a few days thinking it over. He decided to fly out to see me before studying abroad for just a weekend, and we fell seriously so in love again. He had never treated me better and he cried telling me he knows he is hurting me and is sorry. He told me the rebound is just to fill the void, and that he loves me, and wishes we could be in the same place all the time so things could be different.

I finally wrote him an email telling him I cant "work on things" with the rebound in the picture because we have trust issues, and having her on the side is not conducive to trust (they are not dating, just talking everyday). He agreed to drop her although she continued to contact him, and he continued to be good to me for the week before he left the states to go to London. We talked every night, he was flirtatious, and conscious of my feelings, and made sure I knew he was not with anyone else.

He traveled to London last week, and now I became very insecure, him being single and still confused with very limited contact with him bring abroad. I skyped him and broke down in front of him telling him how painful this situation is (relationship limbo). He teared up and said it was all his fault, he just can't let me go, and that if we were in person things would be so different. He told me he will give me space to fully heal, and for me to contact him whenever I'd like. That same night, he reconnected with the rebound and skyped her. They have skyped everyday since I broke down. He has also met a new girl in London--many facebook pics surfaced of him being very flirtatious with her. (Ugh..if one rebound was not enough). Well, we did not talk for 3 days since I broke down, and he skyped me today and things were very good--I tried my best to not bring anything painful up, and it went well and he said he would like to speak to me again. Immediately after, he wrote a very flirtatious message on the rebound's wall--and he has yet to make his relationship with her public because he did not want anyone to know since they started talking.

So my dilemma: after ALL of this... do I go back to limbo and let him be single and figure himself out, and be as positive as possible and hope he realizes he wants me? Or do I go back to NC? The reason I ask is because during the course of all of this he told me when I did NC it pushed him to be with her more, and that me being in his life allows him to see how much he cares about me. But then everyone says to ignore him and he will miss me... both have shown to be true thus far in my case, because as soon as i broke down and told him not to talk to me for a bit, he went straight back to her! Advice please, I'm sorry this is so long--but this is honestly so hard to explain to someone, and I'd really appreciate any words of wisdom. P.S. we will continue to be long distance for a while, and when he heads back to the states he will be with the rebound. :/