Should I choose my ex bf or the new guy?

I was in a relationship with a guy for 8 months, I felt as if I loved him because I cared for him very much. We broke up because I noticed things weren't the same from when the relationship started. He never came over, we never hung out and our conversations were boring. I asked him and he said he had a lot going on in his life, so I asked "do you think you're ready for a relationship?" and his response was "Idk". I'm positive he lied about the reason. I was really sad. So I broke up with him. About two weeks after while I was still depressed over the break up he messages me pictures of us from the fair and said that he looks at them every night. So I thought maybe we could work things out, but That night I also found out that he had asked his ex to go eat. So I got over it and didn't reply. Then he set his best friend as his women crush on instagram and kept snapchatting me pictures of her saying that she was his flower. He also went out to get pizza with a girl who has a boyfriend and he went over to her house and was snapchatting me pictures of them together. He also set her as his women crush on instagram. About a 3 weeks pass and I meet this guy, he's really sweet and has been heartbroken so I can relate. We're still in the friend stage but I feel as if we keep talking, it can get somewhere. All of a sudden my ex messages me apologizing and I don't reply, then he told me he missed me last night and that he was rereading our notes we used to write to each other. He asks to hang out and I tell him that not quite yet maybe later on in the future. Now I cant stop thinking about the memories but I kind of like the new guy. What do I do? To forget my ex cause I feel terrible, I feel as if I made him be sad and I am the kind of person to feel bad.