Voice in my head

I’ve been married for 20 years with 3 kids. We’ve had some rough patches the last year and a half but we’re trying to work them out and stay together! But I have this voice in my head that absolutely hates him, thinks he’s cheating on me, finds the worst in everything he does, never gives him the benefit of the doubt, etc. I know those things that this voice says are not true and I’ve tried to get rid of them but I can’t get them to go away. Is this anxiety?? I’ve never had anxiety but I’m wondering if that’s what it is. But why is it only attacking him and not causing anxiety in any other area of my life??