Fear of losing my partner 😥

It’s 2am here and I’m balling my eyes out thinking about how one day one of us would have to live without the other. I can’t imagine my life without him. He is my world. I don’t know what I would do. And what if I go first? I know it sounds selfish but I would rather go first so I wouldn’t have to deal with the pain but at the same time I don’t want him to feel that pain. Is this normal? I’m so sad and I’m scared. It could be at any moment. My whole life can change in less than a second. My heart is with everyone who has lost their partner.