Break up and he is moving on

So my boyfriend broke up with me almost a month ago. He has broken up with me several times in the past and it never lasts long only a couple days but the longest has been a month. I know are relationship was toxic and most of the time I wasn’t happy but I do love him & he was my first everything. We were together for almost 2 years. I tried to give him the world but he just seemed to be sick of me. When we broke up a couple days later his best friend ask me to meet him at Walmart and he told me that he was already out and buying girls flowers. I knew this break up was going to be one that was going to last. I tried to not care much... but I was upset. His best friend then decided to tell me that he liked me and has always liked me and thought the world of me and told me I deserved better. We spent the rest of the night talking and listening to music. The more time and days that went by I was completely fine. I never thought about my ex at least not that much. I talked to my Ex’s best friend almost everyday and he was like my best friend he kept telling me he wanted to be more but I recently told him I wanted to stay friends and nothing more. I know my Ex has been out with plenty girls and doing things and I never let it bother me but for some reason today he hasn’t really left my mind... & I miss him. I think that’s the first time I have said that since we broke up. I mean I lived with him for almost a year and we have a dog together. She is currently with me but he calls me every once in a while and wants her back then he keeps her some and calls me to come get her. I don’t think he cares much about the dog But for some reason he wants to keep her. He has me blocked on everything but requested to follow a lot of my friends. He can call me but I can’t call him because I’m blocked. I don’t know why I am all of a sudden felling so upset over all of this & why I miss him so much but I wonder if he misses me or if he already has someone new or maybe all the girls are distractions... I need advice on how to move on. I find some flaw in every guy that wants to take me out or has taken me out. There is just always something I don’t like about them and I push them out. What’s the best way of handling this? I don’t know if I should force myself to move on with a guy or should I stay single and possible think about him and miss him more? Do I have anymore options? Any advice?