I can think of two ways to un-crush.

One is to learn about their flaws and weaknesses, so you don't idealize them.

Here, though, you are attracted to their flaws/weaknesses.

The other way I know of to un-crush is to stop all contact.

If not permanently, then at least for a long time.

What if you don't contact either of them for the month of July?

I wonder if there are other gym classes.

If not, "no contact" could be taking a strictly professional approach before, during, and after class. No contact beyond what you would say to any other gym instructor.