Genuinely asking, how do i get over my ex

It has been three months and I am still not over him. He already had a second girlfriend after me and broke up with her too. But I am still thinking about him. Please don't ask me why my self respect is down the drains. I'll appreciate if anyone can share similar experience or real life advices. Also is there any good manga/manhwa that deals with getting over someone in a realistic way and not al just rom-com? I'll really appreciate if someone can help me out thanks :)