Pls help! i wnat him back but he no longer want to?

Im really so heartbroken and i no longer know what to do. I mean i know, but its soo hard to start moving. After 3 months i broke up with my boyfriend and i regret doing it. The issue was my jealousy which is always out of place according to him. And i dont trust him fully because of the history that he has with regard to having many girl friends. I told him i want him back, but then he no longer want to go back. He said he has reached his maximum already. Before he used to say he want to grow old with me, and now, i guess its the opposite already. He wont give me any chance anymore to make things right. It has been 3 days since the break up and he told me he has moved on already. This is my first relationship and my first heart break. I know i need to go on with life, i still have review cles, but i dont have the motivation to go back. I know i need to but i can't. I love him so much but i didn't trust him and he gave up on me. Now i partly blame myself for all of this....