Don't you hate it!

So you all know that I do some karate. So there is that guys at karate, that would once in every blue moon, give me hint that he is attracted to me. Like on Tuesday, I forgot my waterbottle in the gym(our dojo) and only realise it when I had done changing. So I went to check there, I couldn't found it. I had some high hells, and they do make some noise. So he hear me from the changing room(the men changing room has a entry, with no door, leading to the gym). He ask me if it was me taht had forget her bottle. I said yes. He went to get it and give it to me. As i was walking out, he said to me to "stop making some noise". I told him, joking, "do you have a problem with it?"He said to me:"No, with them and those jean is have a great ass."
And what is wrong with that you should ask? He has a girlfriend(I don't know if they married). He might not be the cutest guy, but he is super nice and I'm kind of attracted to him... And I hate it when he does that. He is in a freaking serious relationship! I hate when men does that kind of stuff! It does rub my ego in the good way, but then, I know he is not free, and I'm not confortable even considering that kind of thing!