I am 38, I realise what I am about to post is ridiculous.
Just in case this is relevant at all, I have a partner who I am very attracted to. I've also never been a flirtatious person, I only mention that because I once had a friend who was v flirty and she always seemed to be going crazy over a crush on someone. Again just in case this is relevant at all I've always either been single or in a relationship..never really dating scene or playing the field etc. What I am trying to say is that obviously there are attractive people all over the place but I've never really been the type to be bothered/interested and have only got into relationships when I've known/connected with someone.
About 3 years ago I saw a picture of a celebrity I have known of for years beforehand and never really thought about. For some reason I just kind of thought they were perfect looking and have barely stopped thinking about them since. They play a sport and I watch endless videos of them and look at pictures of them all the time.
Now obviously I know crushing on celebrities is a thing but why am I doing it this much and just on one person, Usually when people are the type to have celeb crushes isn't it more than one and not all day every day?
My DP knows I am a fan of this person, so is he...not for the same reasons as far as I know XD Sometimes he will jokingly ask me, oh so do you think he is handsome? I always change the subject and brush it off because I feel guilty...it's so much more intense than just thinking, oh that man is handsome. If I thought my DP was staring at piks/videos of the same person every single day I would be really hurt.
Covid aside my life has not been easy these last few years and I can only assume this is a symptom of that. I would say I am obsessed really 
Just FYI I have no interest in contacting/seeking out the real person nor do I think me and them are meant to be or anything like that. I think that maybe when my life has got into a bad place I see this person as the opposite of all my problems and I am sort looking to them for inspiration?
I feel alot better and clearer for typing that out, so if you got to the end, thank you!