How to break up with someone you love with

Not going to go in extreme detail because it’s too hard emotionally. But essentially I’m planning on ending my relationship. However I’m still in love with him we just have some fundamental differences I can’t get over. I don’t know how to even do it but I know I have too. He’s just the person I want to call when I see something funny or when I’m sad. He’s my person. Any tips for how to do this and get through it???? This is my first big break up.