Starting to think that my boyfriend is ugly

So I've been with my boyfriend for two years. We are in a long distance relationship now entering our 8 months apart.

We video call every day or at least as much as possible and tonight when I was calling him I suddenly thought that he's kinda ugly but that thought only lasted for a few seconds. I still miss him and feel empty when I don't talk to him though

Now I'm not sure about how I think about that. I don't know what this means. I still remember before I would NEVER think that way about him and always think that he's the most attractive human being. That was the first time that random thought came to me

Why did I think that? What should I do? Do you think it's because we've been apart for a while and will it go away when we see each other again?