Why do I think about these things involving him?

Faith
I've been with my boyfriend for almost 5 years. We've both been through a lot with each other... But I always picture and play through these bad situations in my head with him and get myself upset. Like I imagine what would happen if he cheated on me, if he died, if I caught him cheating on me, us breaking up... And I feel horrible. 😢 Because I love him so much, but why do I do this to myself? 😢