You have to stop talking to him. You love him very much. Your feelings for him are intact. However, his feelings for you are not intact. It doesn't matter if he loves you. What matters is how he feels about you. His feelings for you are no longer the same.
You should allow the breakup to take its course. You are hurting yourself by remaining in the relationship.
You should stop talking to him. It is difficult but you will have to discipline yourself not to talk to him. The more you talk to him the more you are hurt. He made his decision, you have to make your decision. He has a decision to make: remain in your camp or leave for good.
Even if he remains in the relationship, it will serve the relationship no good. This is because of the feelings he has for the girl.
You have been in the relationship for a lengthy time. You can't afford to waste more time waiting for him or trying to get him back. You should move on with your life.
Remember, you have a life to live. It will be difficult to move on and your studies will be affected by the breakup. However in time, you will have receovered from the breakup.
Don't be in a relationship with a man whose feelings aren't intact or whose feelings are wavering. Why? This is because in the end, the man will dump you and join the other camp.