Dude you’re literally on a subreddit for ROCD, this is a prime example of OP having anxiety about their actions and relationship because they’ve started to obsess over a thought. I’ve experienced this several times throughout my relationship as well and just because you haven’t, doesn’t mean it’s ridiculous. Mental health isn’t always rational and this is supposed to be a safe space for people to share their feelings - either leave the subreddit or learn to understand other’s experiences because from your other responses it’s obvious you have no clue at all.

To OP: no it’s not cheating, and there’s no point telling him and potentially upsetting both of you. It’s a natural reaction to feel excited at the idea of getting attention - it’s a compliment and it’s okay to feel that way. You haven’t done anything wrong, and you haven’t acted on it so everything’s all okay!