I need advice

So this is more of a personal note, im confused on what to do. Me and this guy dated for about one year. He was my first love, my first boyfriend. Unfortunately I wasn't his. He broke up with me because he said that he wanted to focus on school. I totally understand that, I will never want to make him loose his priority of school because I know its important. We have been broken up for about 2 months already, and I couldn't be any more saddened. I took him off from everything except my number and WhatsApp. He would always ask me how I was doing, if I had eated or I was was sleeping ok. Im not sure if he genuinely cared or idk. If I wouldn't answer him or something he would ask mutalk friends how I was doing or stuff like that. To be honest I miss him so much. The only thing is that I found out that when we broke up he joined dating sites the very next day. I was also able to find out that he had talked to his ex and slept on the phone while we were together. Now this is a big deal because I feel like he hasn't gotten over her. Now yesterday he messed me and told me how much he missed me and that he was able to see a future with me and all that stuff. Im not sure of what to do, I do want him back because I just miss him so much but... I dont know what to do. Does anyone have any advice?