I have a teacher that I meet every Monday and Wednesday. He's very good-looking and educated. His personality is also so sweet and nice. I get so tense around him and he knows by my facial and body language. I think that I'm his favorite student due to the way he treats me and acts towards me but he doesn't like showing it. I can't stop thinking about him. I'm just worried about how this could turn into a crush or something even more deeper than that even though he already has a girlfriend and I respect that. Ugh this makes me cringe so hard lol. Any advice?

Personally I think you just need to let time run it's course. I've been in situations like this before, not with a teacher but similar, and this was the best method. Remind yourself this is a professional relationship, you aren't meeting this person just cause, you're meeting them because of a task. While you may connect a little more personally from time to time, always bring it back to being professional in your mind. That said, I would usually recommend in any situation that limiting exposure is always a good way to avoid anything developing, but, that said, your exposure is already rather limited and it's professional setting already so I think this parts okay. With that in mind, you only seeing this person 2 times a week leaves you with plenty of other time/ days to be doing other things. Granted I don't know your life, but filling your free days/hours with random activities is an easy way to start working on getting rid of the "I can't stop thinking about him problem". I'm not going to say it'll fully get rid of that problem, but as long as you can find other engaging and fun activities to do to entertain yourself, It'll begin lessening how much time you spend thinking about the person on a day to day basis. This will also help you no longer feel overwhelmed (not saying you are) with emotion about this person and critically think about your relationship with them.

The activities you can take on may include things such as hanging out with friends, getting a coffee, finding a new show/book series you are super into, finding a videogame you may like to play, picking up a new hobby like drawing or biking, and going on nature walks. There's a plethora of stuff you can do. The main point of it is to be engaged, because if you aren't engaged it isn't hard to start going through the motions and find yourself thinking about the person even while doing a new activity.

I hope this all helps. Best of luck.