Letting Go

Does anyone actually know how to let go of someone?? Or does that take time??

I'm trying to let go of my toxic boyfriend. Tomorrow is 5 months since we broke up and I don't want be here sad and hurt over him while he doesn't care. It's not fair to me but at the same time I really don't know how to let go. Please tell me what I can do to let go. TIA 🧡