Well, I can’t say this might be the case for you, but this might be something to consider.
Sometimes I like the idea of sex for the emotional connection that it can create. I like sex for nonsexual reasons, if that makes sense, it’s just another way to get closer to someone. I don’t really consider it or feel anymore about it than this community on average feels about cuddling, because it’s kinda just another way to cuddle for me, if that makes sense.
As ridicules as it might sound, perhaps sexual attraction could be compared to food cravings? Swap out the food for a person and bam! Is that how you feel about him?
Are these thoughts intrusive, or are they somewhat more willing but equally as annoying, as though you can’t stop thinking about it? I’ve had fantasy before, but it was never something that I couldn’t really just stop at a moments notice, or that I particularly wanted in any other area than imagining the emotion that it might create. The point is, that I was in control of it, and it was reflective of my attitude and feelings towards sex in general. Intrusive thoughts are very real, and they can happen about anything, could that be what you’re experiencing here? If so, you wouldn’t be the first person on this sub’, you’re not alone with that.
Just remember, it’s whatever you feel comfortable with at the time. If you feel you identify with asexuality for now, then go for it. If you find out it doesn’t fit you later, then that’s fine too. Just try not to worry about it too much, words aren’t set in stone